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Abelmoschus esculentus +Fertile, well-drained soil with ample moisture, waste places  +
Abies amabilis +Moist, coastal coniferous forests  +
Abies balsamea +Boreal and northern forests  +
Abies bifolia +Continental, subalpine coniferous forests  +
Abies bracteata +Dry, coastal coniferous forests  +
Abies concolor +Coniferous forests  +
Abies fraseri +Mountain forests  +
Abies grandis +Moist, coastal coniferous forests and mountain slopes  +
Abies lasiocarpa +Coastal, subalpine coniferous forests  +
Abies lowiana +Mixed coniferous forests  +
Abies magnifica +Mixed coniferous forests  +
Abies procera +Mixed coniferous forests  +
Abietinella abietina +Dry, exposed calcareous rock and soil, sand of partially stabilized dunes, talus at base of cliffs, humus in open, coniferous forests  +
Abildgaardia ovata +Rocky, gravelly savanna, solution pockets in limerock  +
Abronia alpina +Sandy soils, alpine meadows  +
Abronia ameliae +Sandy soils, live-oak grasslands  +
Abronia ammophila +Sandy soils, lake shores  +
Abronia angustifolia +Sandy soils, desert scrub  +
Abronia argillosa +Clay soils, desert scrub to pinyon-juniper woodlands  +
Abronia bigelovii +Shrubby gypsum hills  +
Abronia bolackii +Gypseous sandy or gravelly soils, open areas, among sparse shrubs  +
Abronia carletonii +Calcareous or gypseous, clay or silty soils, shrublands  +
Abronia elliptica +Sandy or gravelly soils, desert grasslands, scrub  +
Abronia fragrans +Dry sandy soils, scrub and grasslands  +
Abronia latifolia +Sandy soils, coastal scrub, lees of dunes adjacent to strand  +
Abronia macrocarpa +Sand dunes  +
Abronia maritima +Foredunes and unstable dunes near strand  +
Abronia mellifera +Sandy soils, cold desert scrub, grasslands  +
Abronia nana var. covillei +Dry sandy and rocky areas, pinyon-juniper woodlands, yellow-pine forests  +
Abronia nana var. nana +Rocky limestone, scrub, pinyon-juniper woodlands, pine forests  +
Abronia pogonantha +Sandy soils, Joshua tree desert scrub  +
Abronia turbinata +Sandy soils, desert scrub  +
Abronia umbellata var. acutalata +Sandy soils, coastal scrub, lees of dunes near strand  +
Abronia umbellata var. breviflora +Sandy soils, coastal scrub, lees of dunes near strand  +
Abronia umbellata var. umbellata +Sandy soils, coastal scrub, lees of dunes near strand  +
Abronia villosa var. aurita +Sandy soils, sage-scrub, chaparral  +
Abronia villosa var. villosa +Sandy soils, creosote bushscrub  +
Abutilon abutiloides +Open, arid habitats  +
Abutilon berlandieri +Open, arid habitats  +
Abutilon coahuilae +Open, arid habitats  +
Abutilon fruticosum +Open, arid habitats  +
Abutilon hirtum +Disturbed sites  +
Abutilon hulseanum +Roadsides, disturbed sites, secondary vegetation  +
Abutilon hypoleucum +Dry shrublands, roadsides, disturbed sites  +
Abutilon incanum +Open, arid habitats, hills and plains  +
Abutilon malacum +Arid habitats, hillsides, plains, canyons  +
Abutilon mollicomum +Open desert habitats, along water courses  +
Abutilon palmeri +Desert habitats  +
Abutilon parishii +Mountain slopes, desert scrublands  +
Abutilon parvulum +Dry, open habitats  +
Abutilon permolle +Coastal areas, disturbed sites, often on limestone soil  +
Abutilon reventum +Arid hillsides, along water courses  +
Abutilon theophrasti +Soybean, corn, and cotton fields, naturalized in disturbed sites  +
Abutilon trisulcatum +Dry shrublands, disturbed vegetation, roadsides  +
Abutilon wrightii +Dry, open habitats, roadsides  +
Acaena novae-zelandiae +Roadsides and paths, forest edges, logged lands, lawns, among cultivated ground covers and waste grounds  +
Acaena pallida +Coastal sands  +
Acaena pinnatifida +Coastal grasslands, open rocky slopes, sand dunes, old roadsides  +
Acalypha alopecuroidea +Disturbed areas.  +
Acalypha arvensis +Disturbed areas.  +
Acalypha australis +Disturbed areas.  +
Acalypha californica +Arid rocky slopes, desert washes.  +
Acalypha chamaedrifolia +Rocky pine woods, disturbed areas.  +
Acalypha deamii +Moist bottomland woods, near streams or rivers, rarely in moist upland forests.  +
Acalypha gracilens +Pine and pine-oak woods, dry hardwood forests, glades, prairies, disturbed areas, usually on sand or shallow rocky soils.  +
Acalypha monococca +Pine and oak woods, prairies, barrens, on sandy or shallow rocky soils.  +
Acalypha monostachya +Dry, open, rocky, gravelly, or sandy areas.  +
Acalypha neomexicana +Moist or shaded areas, oak or pine woodlands, desert grasslands.  +
Acalypha ostryifolia +Stream banks, edges of woods, disturbed areas, agricultural fields.  +
Acalypha phleoides +Rocky areas, grasslands, oak, pine, or juniper woodlands.  +
Acalypha poiretii +Disturbed areas.  +
Acalypha radians +Grassy openings, dunes, and oak or mesquite woodlands, usually on deep sand.  +
Acalypha rhomboidea +Deciduous and evergreen woods, moist depressions, swampy areas, riverbanks, agricultural fields, disturbed areas.  +
Acalypha setosa +Disturbed areas.  +
Acalypha virginica +Deciduous and evergreen woods, riverbanks, agricultural fields, disturbed areas.  +
Acalypha wilkesiana +Old home sites, disturbed areas.  +
Acamptopappus shockleyi +Mesas, ridges, slopes, ravines, washes, in various shrub associations, commonly with Larrea, Yucca, Ambrosia, Artemisia, Ephedra, Atriplex  +
Acamptopappus sphaerocephalus var. hirtellus +Gravelly soils, deserts, juniper woodlands  +
Acamptopappus sphaerocephalus var. sphaerocephalus +Gravelly, rocky soils, grasslands, deserts, woodlands  +
Acanthocereus tetragonus +Sandy soils of dense thickets, hammocks, bottomlands of coastal areas  +
Acanthoscyphus parishii var. abramsii +Sandy flats and slopes, chaparral communities, montane conifer woodlands  +
Acanthoscyphus parishii var. cienegensis +Sandy flats and slopes, montane conifer forests  +
Acanthoscyphus parishii var. goodmaniana +Sandy calcareous slopes, chaparral communities  +
Acanthoscyphus parishii var. parishii +Sandy to gravelly flats and slopes, chaparral communities, montane conifer woodlands  +
Acanthospermum australe +Disturbed, often sandy sites  +
Acanthospermum hispidum +Disturbed, often sandy sites  +
Acanthospermum humile +Disturbed, often sandy sites  +
Acaulon muticum var. muticum +Soil, among grasses, pastures  +
Acaulon muticum var. rufescens +Soil, gravel pit, pasture, lawn  +
Acaulon schimperianum +Soil, dry washes  +
Acaulon triquetrum +Soil, sand, clay, old fields, pastures, roadside banks, temporarily moist areas  +
Achillea alpina +Meadows, forest edges, roadsides, lakeshores, along streams, moist soils  +
Achillea millefolium +Pastures, meadows, roadsides, stream sides, woodlands, waste grounds, dry or sandy soils, also in damp, clayey, and salty soils  +
Achillea nobilis +Pastures, disturbed roadsides  +
Achillea ptarmica +Roadsides, disturbed sites, open fields and pastures, in sandy or gravelly soils or in moist to drying silty soils  +
Achlys californica +Coastal and mountainous regions, Sequoia sempervirens and Pseudotsuga menziesii forests  +
Achlys triphylla +Mountain regions in Cascade Range and Coast Range of California in coniferous forests  +
Achyrachaena mollis +Grassy, often wet sites, usually with clay-rich soils  +
Achyranthes aspera var. aspera +Dry, sandy waste places, near woolen mills  +
Achyranthes aspera var. pubescens +Waste places, chrome ore piles, hammocks  +
Achyranthes japonica +Wooded riverbanks  +
Achyronychia cooperi +Dry, sandy areas, sand dunes, desert washes  +
Acleisanthes acutifolia +Calcareous or gypseous soils in grasslands and shrublands  +
Acleisanthes angustifolia +Arid, well-drained, often rocky, igneous, calcareous, or gypseous soils  +
Acleisanthes anisophylla +Rocky, gravelly, or sandy soils, limestone or shale outcrops in grasslands or shrublands  +
Acleisanthes chenopodioides +Dry, sandy, and gravelly areas, rock, gypseous clay  +
Acleisanthes crassifolia +Rocky, calcareous soils in cenizo (Leucophyllum frutescens) shrublands and grasslands  +
Acleisanthes diffusa +Dry clay and sandy, commonly calcareous or gypseous, soils  +
Acleisanthes lanceolata var. lanceolata +Gypsum hills and flats  +
Acleisanthes longiflora +Rocky, gravelly, loamy, or sandy calcareous, gypseous, or igneous-derived soils in deserts, grasslands, shrublands, or woodlands  +
Acleisanthes nevadensis +Dry rocky soils, commonly with Larrea  +
Acleisanthes obtusa +Sandy, silty, or clay soils on calcareous or igneous substrates in grasslands, shrublands, or woodlands  +
Acleisanthes parvifolia +Dry gypseous clays and shales  +
Acleisanthes wrightii +Various soils on calcareous substrates in grasslands or shrublands  +
Acmella pusilla +Disturbed sites  +
Acmella repens +Disturbed, wet or drying sites  +
Acoelorraphe wrightii +Thin, rocky soil over limestone in hydric hammocks, wet savannas, and swamps of Everglades  +
Aconitum columbianum subsp. columbianum +Spring-fed bogs, seep areas, meadows, along streams, and in other wet areas  +
Aconitum columbianum subsp. viviparum +Spring-fed bogs, seep areas, meadows, along streams, and other moist areas in mountains  +
Aconitum delphiniifolium +Meadows, along creeks, thickets, woods, rocky slopes, and alpine tundra  +
Aconitum maximum subsp. maximum +Meadows, thickets, and forests  +
Aconitum reclinatum +Shaded ravines of woods in mountains and upper piedmont  +
Aconitum uncinatum +Wet areas along streams and in springs, also less mesic locations in woods and clearings  +
Aconogonon alaskanum var. alaskanum +Montane slopes above treeline, steep hillsides, steep cut banks or sandy loam of rivers  +
Aconogonon alaskanum var. glabrescens +Moist hillsides, waste places, streambanks, sandy lake shores, talus slopes above treeline  +
Aconogonon davisiae var. davisiae +Steep subalpine slopes, volcanic fell fields, often on talus or pumice  +
Aconogonon davisiae var. glabrum +Mountain slopes, talus slopes, edges of serpentine outcrops  +
Aconogonon phytolaccifolium var. glabrum +Sandy to rocky spruce-fir forests  +
Aconogonon phytolaccifolium var. phytolaccifolium +Alpine and subalpine meadows, talus slopes, streambanks  +
Acorus americanus +Wet open areas, marshes, swales, and along edges of quiet water  +
Acorus calamus +Wet open areas, marshes, swales, and along edges of quiet water  +
Acourtia microcephala +Gravel and caliche soils in scrub oak, oak woodlands, and chaparral  +
Acourtia nana +Gravel, sandstone, silty, or caliche soils in desert scrub  +
Acourtia runcinata +Juniper forests, oak woodlands, dry matorral, desert scrub on calcareous, sandy clay, and gypsiferous soils  +
Acourtia thurberi +Gravel and caliche soils in warm Sonoran desert scrub  +
Acourtia wrightii +Gravel, caliche, or sandy loamy soils in open desert (Lower Sonoran Desert)  +
Acrocomia totai +Woodlands and hammocks  +
Acroporium smallii +Rotten logs, tree bark, charred wood, moist live-oak hammocks  +
Acroptilon repens +Fields, roadsides, riverbanks, ditch banks, clearcuts, cultivated ground  +
Acrostichum aureum +Coastal mangrove swamps, salt marshes, low hammocks, along lake and canal margins  +
Acrostichum danaeifolium +Somewhat saline to freshwater swamps, canal and pond margins, commonly in sinkholes in hammocks, disturbed marl sites, inland to coastal regions  +
Actaea pachypoda +Deciduous forests, less often with pines, junipers, or other conifers  +
Actaea rubra +Mostly deciduous forests, also mixed coniferous forests, open pine or spruce woodlands, swales, stream banks, and swamps  +
Actinostachys pennula +On and around rotten stumps and decomposing litter in damp forests and open baylands.  +
Adelia vaseyi +Subtropical semideciduous woodlands on loamy soils, occasionally shrublands on sandy to gravelly soils.  +
Adenocaulon bicolor +Woods, forests, usually in shade  +
Adenophyllum cooperi +Sandy and gravelly soils of washes and alluvial fans in deserts  +
Adenophyllum porophylloides +Alluvial fans and rocky slopes in deserts  +
Adenophyllum wrightii var. wrightii +Wettish sites in otherwise arid areas, coarse, sandy alluvium  +
Adenostoma fasciculatum var. fasciculatum +Dry slopes, ridges, lower chaparral and coastal sage scrub  +
Adenostoma fasciculatum var. obtusifolium +Mesas, ravines, coastal sage scrub-chaparral  +
Adenostoma fasciculatum var. prostratum +Maritime chaparral  +
Adenostoma sparsifolium +Dry granitic slopes, mesas, ravines, chaparral, pinyon woodlands  +
Adiantum aleuticum +Wooded ravines, shaded banks, talus slopes, serpentine barrens, and coastal headlands (uncommon)  +
Adiantum capillus-veneris +Moist calcareous cliffs, banks, and ledges along streams and rivers, walls of lime sinks, canyon walls (in the American southwest), around foundations, on mortar of storm drains  +
Adiantum hispidulum +Banks and old walls  +
Adiantum jordanii +Seasonally moist, shaded, rocky banks, canyons, and ravines  +
Adiantum melanoleucum +Hammocks and limestone sinks in Everglades National Park  +
Adiantum pedatum +Rich, deciduous woodlands, often on humus-covered talus slopes and moist lime soils  +
Adiantum tenerum +Restricted to moist, shaded, limestone ledges, sink walls, and grottoes in the flora  +
Adiantum tricholepis +Moist, shaded, limestone cliffs along streams and rivers, on boulders in creeks, and among rocks on steep slopes  +
Adiantum viridimontanum +Restricted to serpentine sites where it occurs in rock clefts, on talus slopes, and in well-developed serpentine soils  +
Adlumia fungosa +Moist coves, rocky woods, ledges, alluvial slopes, and thickets  +
Adolphia californica +Rocky slopes, dry canyons and washes, fields, roadsides, arroyos and hillsides near seeps, streambeds, chaparral, coastal sage scrub.  +
Adolphia infesta +Open slopes and washes, rocky outcrops, limestone and igneous substrates, roadsides, chaparral, oak-juniper and mixed conifer-oak woodlands.  +
Adonis aestivalis +Roadsides, fields, sagebrush scrub, and open pine or aspen forests in valleys and foothills  +
Adonis annua +Prairies, fields, river banks, and waste places  +
Adonis vernalis +Roadsides and sites adjacent to gardens  +
Aeonium arboreum var. arboreum +Cliffs and banks near sea  +
Aeonium haworthii +North-facing cliffs in canyons and above sea  +
Agalinis aphylla +Bogs, wet flatwoods, hydric savannas, seepage slopes.  +
Agalinis aspera +Tallgrass or loess hills or upland prairies, dry rocky or sandy soils over limestone, limestone bluffs, gravelly moraines.  +
Agalinis auriculata +Seasonally wet meadows, mesic prairies, glades, roadsides, fallow fields.  +
Agalinis caddoensis +Oak woods, dry loamy soils.  +
Agalinis calycina +Wet alkaline, saline meadows and marshes associated with springs and seeps.  +
Agalinis decemloba +Sand plain grasslands, dry prairie remnants, dry roadsides, cemeteries, margins and openings in mesic to dry mixed woodlands, serpentine grasslands.  +
Agalinis densiflora +Prairies, grassy roadsides, pastures, well-drained calcareous soils.  +
Agalinis divaricata +Dry open pine savannas, dry oak openings, dry sandy ground, mesic flatwoods, margins of bogs and seepage slopes, dry roadsides.  +
Agalinis edwardsiana +Grasslands, open rocky slopes, calcareous, clay or sandy soils.  +
Agalinis fasciculata +Dry or wet sandy ground, waste places, roadsides, ditches, pastures, fallow fields, alluvial ground of streams, brackish soils, thickets, lawns.  +
Agalinis filicaulis +Mesic to moist longleaf pine forests, moist prairies, shallow bogs, moist roadsides, remnant wiregrass communities, borrow pits.  +
Agalinis filifolia +Xeric, sandy, open pine forests, open coastal scrub habitats, dunes, open areas of pine flatwoods, hydric soils of pine flatwoods.  +
Agalinis flexicaulis +Mesic to moist soils, open, wiregrass-dominated longleaf pine systems, savannas, prairies, seepage slopes, depressed wetlands, disturbed ground.  +
Agalinis gattingeri +Dry roadsides, open woodlands, forest margins, mesic prairies, glades, bluffs, exposed ridges, alvars, often in cherty limestone, or sandy, rocky soils.  +
Agalinis georgiana +Dry or moist longleaf pine savannas, oak openings, wiregrass-dominated seepage slopes, margins of bogs.  +
Agalinis harperi +Wet to mesic savannas, bogs, wet prairies, borders of fresh to brackish marshes, roadsides and ditches, drier sites near these habitats.  +
Agalinis heterophylla +Moist open sites, moist prairies, margins of mesic to wet forests, fallow fields, roadsides, ditches, margins of marshes and ponds, disturbed sandy soils.  +
Agalinis homalantha +Dry, open woodlands, dry to xeric sandy terrace communities above streams, dry roadsides, open sandy habitats.  +
Agalinis laxa +Dry to mesic pinelands, pine and oak savannas, sand hills, openings in saw palmetto flatwoods, sandy soils.  +
Agalinis linifolia +Wet savannas and prairies, depressed areas of mesic savannas or open flatwoods, bogs, margins and centers of cypress domes, margins of ponds, lakes, brackish and freshwater marshes, open stream banks, roadsides, ditches.  +
Agalinis maritima var. grandiflora +Saline coastal areas, salt marshes, edges of saline or brackish pools, open salt terns, edges of ditches, salt flats, and tidal flats.  +
Agalinis maritima var. maritima +Salt marshes, salt flats, tidal flats, edges of saline or brackish pools, ditches.  +
Agalinis navasotensis +Rocky prairie remnants on sandstone outcrops, sandy clay soils of longleaf pine savannas.  +
Agalinis neoscotica +Sandy or peaty soils, margins of pools, lakes, bogs, estuaries, and marshes, sand flats, dune hollows, ditches.  +
Agalinis obtusifolia +Mesic to dry savannas, dry roadsides with native vegetation, open rocky ground, open pine flatwoods, cutover and edges of pine plantations, margins of bogs and seepage slopes.  +
Agalinis oligophylla +Moist to dry longleaf pine savannas, edges of pine plantations, dry roadsides, chalky outcrops, seepage slopes of clay roadsides.  +
Agalinis plukenetii +Dry to xeric, sandy, gravelly or clay roadsides, pine-oak forests, margins of savannas, disturbed ground.  +
Agalinis pulchella +Dry, open pine savannas, open pine-oak sandhills, dry upslope areas of wiregrass-dominated mesic prairies, chalky glades or roadsides, dry sandy or clay roadsides beside existing or remnant savannas.  +
Agalinis purpurea var. parviflora +Moist sandy, clay, or peaty soils at margins of ponds, lakes, streams, bogs, freshwater or brackish marshes, ditches, roadsides.  +
Agalinis purpurea var. purpurea +Moist sandy soils at margins of ponds, lakes, streams, bogs, freshwater and brackish marshes, ditches, pine barrens, meadows, prairies, coastal swales, dry soils, margins of pine plantations, inundated marl prairies.  +
Agalinis setacea +Dry sandy soils, pine savannas, margins of pine-oak woodlands and scrub, sand hills, roadside embankments.  +
Agalinis skinneriana +Dry to mesic areas in sand and loess hill prairies, bluff prairies, dolomite glades, dunes, open woods, areas of low and/or sparse herbaceous cover.  +
Agalinis strictifolia +Grasslands, old fields, pastures, open mesquite plains, dunes along Gulf Coast.  +
Agalinis tenella +Dry sandy to mesic pine savannas, margins of pine plantations, mixed open woodlands and oak-pine scrub, open pine-palmetto palm woodlands, ditch banks, sandy embankments, roadsides.  +
Agalinis tenuifolia +Wet to dry roadsides, ditches, margins of streams and ponds, borders of woodlands, dry to moist prairies, fallow fields, railroad embankments, rocky cliff faces and bluffs.  +
Agalinis viridis +Mesic to wet areas of prairies, moist to wet savannas, moist roadsides, mesic to wet edges of recently clear-cut forests, dry or wet roadsides.  +
Agarista populifolia +Acid swamps to moist broadleaved forests, especially along streams, in ravines, or near springs  +
Agave americana subsp. protamericana +Sandy places in desert scrub  +
Agave americana var. americana +Sandy places in desert scrub  +
Agave americana var. expansa +Sandy places in desert scrub and grasslands  +
Agave asperrima var. asperrima +Sandy to gravelly, often calcareous places in desert scrub  +
Agave chrysantha +Sandy to gravelly places on granitic or volcanic soils in desert scrub, grasslands, pinyon-juniper, and oak woodlands  +
Agave decipiens +Sandy soil in hammocks  +
Agave delamateri +Gravelly places with desert scrub, rarely in chaparral or pinyon-juniper woodlands  +
Agave deserti var. deserti +Sandy to gravelly or rocky places in desert scrub and pinyon juniper woodlands  +
Agave deserti var. simplex +Sandy to gravelly or rocky places in desert scrub and pinyon juniper woodlands  +
Agave desmettiana +Sandy places along roadsides and in hammocks  +
Agave gracilipes +Gravelly to rocky, often calcareous places in grasslands, desert scrub, and pinyon juniper woodlands  +
Agave havardiana +Gravelly to rocky, often calcareous places in grasslands, desert scrub, pinyon-juniper, and oak woodlands  +
Agave lechuguilla +Gravelly to rocky calcareous places in desert scrub  +
Agave mckelveyana +Sandy to gravelly or rocky places with desert scrub, chaparral and pinyon-juniper woodlands  +
Agave murpheyi +Near drainage systems in desert scrub  +
Agave neglecta +Sandy places near beaches  +
Agave palmeri +Sandy to gravelly places on limestone in oak woodlands and grassy plains  +
Agave parryi subsp. neomexicana +Gravelly to rocky places in grasslands and desert scrub  +
Agave parryi var. couesii +Gravelly places in grasslands, chaparral, pinyon-juniper, and oak woodlands  +
Agave parryi var. huachucensis +Gravelly places in oak and pine woodlands  +
Agave parryi var. parryi +Gravelly to rocky places in grasslands, desert scrub, chaparral, pinyon-juniper, and oak woodlands  +
Agave parviflora subsp. parviflora +Open rocky slopes, mostly in desert grasslands and oak woodlands  +
Agave phillipsiana +Sandy to gravelly places with desert scrub  +
Agave schottii var. schottii +Gravelly to rocky places, mostly in desert scrub, grasslands, juniper and oak woodlands  +
Agave schottii var. treleasei +Gravelly to rocky places, mostly in desert scrub, grasslands, juniper and oak woodlands  +
Agave shawii var. shawii +Coastal bluffs with coastal sage scrub and chaparral  +
Agave sisalana +Sandy places along roadsides and in hammocks  +
Agave toumeyana var. bella +Open gravelly to rocky limestone or basalt slopes, mostly with desert scrub, chaparral, and pinyon?juniper woodlands  +
Agave toumeyana var. toumeyana +Open gravelly to rocky limestone or basalt slopes, mostly with desert scrub, chaparral, and pinyon-juniper woodlands  +
Agave univittata +Sandy flats  +
Agave utahensis +Calcareous outcrops with desert scrub  +
Agave utahensis subsp. kaibabensis +Calcareous or sandstone outcrops in desert scrub, pinyon-juniper, or adjacent conifer woodlands  +
Agave utahensis subsp. utahensis +Calcareous outcrops with desert scrub  +
Agave utahensis var. eborispina +Calcareous outcrops with desert scrub  +
Agave utahensis var. utahensis +Calcareous outcrops with desert scrub  +
Agave weberi +Sandy places with grasses and low shrubs  +
Agave ×ajoensis +Rocky slopes in desert scrub and grasslands  +
Agave ×arizonica +Rocky slopes in chaparral and juniper-dominated grasslands  +
Agave ×glomeruliflora +Gravelly calcareous slopes in grasslands and oak-juniper woodlands  +
Agdestis clematidea +Hammocks, orchards, waste places, ravines  +
Ageratina adenophora +Stream margins, ditches, road embankments, hillsides  +
Ageratina altissima var. altissima +Moist forests, cove forests  +
Ageratina altissima var. roanensis +Moist forests, northern red oak, oak-chestnut, cove forests  +
Ageratina aromatica +Sandy soils, burned pinelands, turkey oak sand ridges, pine-oak and oak-hickory upland woods, old fields, roadsides, fencerows, moist sites  +
Ageratina havanensis +Bluffs, limestone outcrops and slopes, ledges along streams, often in oak-juniper woodlands  +
Ageratina herbacea +Pine, pine-oak, juniper, and pinyon-juniper woodlands, rocks along streams, slopes, ridges, washes  +
Ageratina jucunda +Sand pine scrub, longleaf pine-turkey oak sand ridges, pine-palmetto, live-oak woods, hammocks, dunes, roadsides, old fields, stream banks, dry flatwoods  +
Ageratina lemmonii +Rocky slopes, mostly in pine-oak woodlands  +
Ageratina luciae-brauniae +Under overhanging sandstone (Pottsville formation) cliffs and ledges  +
Ageratina occidentalis +Crevices, outcrops, rocky slopes, ridges, talus, gravelly and sandy stream bars, mixed hardwood-conifer woodlands, aspen, open and brushy vegetation  +
Ageratina paupercula +Rocky slopes, crevices, gravelly, sandy streambeds, pine-oak woodlands  +
Ageratina rothrockii +Rocky slopes and ledges, in oak-juniper, pine-oak, pine, aspen, and spruce-fir woodland  +
Ageratina shastensis +Cracks and crevices of nearly vertical limestone cliffs  +
Ageratina thyrsiflora +Rocky sites, oak woodland  +
Ageratina wrightii +Limestone slopes, ledges, alluvium, in brushy vegetation  +
Ageratum conyzoides +Disturbed sites, mostly coastal  +
Ageratum corymbosum +Crevices, ledges, cliffs, other rocky sites in canyons, along streams, in desert grasslands, oak-agave, oak, oak-juniper, and pine-oak woodlands  +
Ageratum houstonianum +Disturbed sites, mostly coastal  +
Ageratum maritimum +Beach sand and nearby thickets, coral soils, salt marshes, hammocks, roadsides  +
Agnorhiza bolanderi +Openings in chaparral  +
Agnorhiza elata +Open pine forests  +
Agnorhiza invenusta +Openings in chaparral and in pine and oak forests  +
Agnorhiza ovata +Grassy slopes, openings in pine forests  +
Agnorhiza reticulata +Chaparral, oak woodlands  +
Agoseris apargioides var. apargioides +Coastal dunes  +
Agoseris apargioides var. eastwoodiae +Coastal dunes and beach heads  +
Agoseris apargioides var. maritima +Coastal dunes, sand hills, and beach heads  +
Agoseris aurantiaca var. aurantiaca +Wet meadows, bogs, muskegs, stream and lake margins, montane to alpine habitats, or ± drier sites of open forests and mountain slopes, various soils, often disturbed areas, roadsides  +
Agoseris aurantiaca var. purpurea +Moist, subalpine meadows and forests to alpine tundra, often disturbed areas  +
Agoseris glauca var. dasycephala +Moist to dry habitats, alpine meadows, montane forests, northern prairies, arctic tundra, in gravelly, rocky, and other coarse-textured soils  +
Agoseris glauca var. glauca +Wet meadows, stream margins, swales, other moist sites, grasslands, steppes, and meadow habitats, slightly alkaline or saline sites, mostly in silts, clays, and other fine-textured soils  +
Agoseris grandiflora var. grandiflora +Mesic to dry meadows, grasslands, sagebrush steppes, open oak or coniferous woodlands, chaparral  +
Agoseris grandiflora var. leptophylla +Moist to dry lowland prairies, coastal forests, open coniferous woodlands  +
Agoseris heterophylla var. cryptopleura +Mesic to dry habitats in grasslands, chaparral, oak woodlands, and open pine forests  +
Agoseris heterophylla var. heterophylla +Wet to dry, mostly seasonal habitats in deserts, grasslands, chaparral, steppe, oak woodlands, and open pine forests, often disturbed sites  +
Agoseris heterophylla var. quentinii +Mesic to dry habitats in deserts, grasslands, and oak woodlands  +
Agoseris hirsuta +Mesic to dry grasslands, oak woodlands, and coastal scrub-lands  +
Agoseris monticola +Mesic subalpine meadows and forests to alpine tundra and rocky slopes, volcanic or pyroclastic soils  +
Agoseris parviflora +Dry habitats, sandy soils, short-grass prairies, sagebrush steppes, pinyon-juniper woodlands, montane meadows, mixed conifer forests  +
Agoseris retrorsa +Mesic to dry habitats in scrub-lands, chaparral, steppe, and open oak or pine woodlands  +
Agoseris ×elata +Lowland prairies  +
Agrimonia gryposepala +Edges, open spaces, and thickets, deciduous or mixed pine-deciduous woods  +
Agrimonia incisa +Dry to moist, longleaf pine-oak woods, oak-hickory slopes, roadsides, sand or shell maritime thickets  +
Agrimonia microcarpa +Edges, open spaces and thickets, deciduous or mixed pine-deciduous woods  +
Agrimonia parviflora +Edges, open spaces, thickets deciduous or mixed woods and thickets in wet places  +
Agrimonia pubescens +Edges, open spaces, thickets, deciduous or mixed deciduous woods  +
Agrimonia rostellata +Edges, open spaces, and thickets, deciduous or mixed deciduous woods  +
Agrimonia striata +Edges, open spaces, thickets, in deciduous or mixed deciduous woods  +
Agrostemma githago var. githago +Fields, roadsides, waste places  +
Akebia quinata +Waste places, open woodlands  +
Alcea rosea +Disturbed sites, roadsides, vacant lots  +
Alcea rugosa +Disturbed sites, roadsides, vacant lots  +
Alchemilla alpina +Meadows, herb slopes, moist rock ledges  +
Alchemilla filicaulis subsp. filicaulis +Moist meadows, herb slopes, often near seashores  +
Alchemilla filicaulis subsp. vestita +Moist to mesic meadows, herb slopes, sometimes near seashores  +
Alchemilla glabra +Meadows  +
Alchemilla glaucescens +Waste ground  +
Alchemilla glomerulans +Moist herb slopes, willow scrub  +
Alchemilla micans +Meadows, moist sand  +
Alchemilla mollis +Densely vegetated lake shores  +
Alchemilla monticola +Meadows, lawns, ditches, under trees  +
Alchemilla subcrenata +Moist grasslands, flood plains  +
Alchemilla venosa +Grasslands, often near sea shores  +
Alchemilla wichurae +Moist herb slopes  +
Alchemilla xanthochlora +Moist meadows, herb slopes, willow scrub, ditches, lawns  +
Aletris aurea +Dry to wet pine flatwoods, savannas, and bogs  +
Aletris bracteata +Everglades, pinelands  +
Aletris farinosa +Open sites of various habitats, moist bogs, dry to mesic prairies, and dry, upland woods and thickets  +
Aletris lutea +Seasonally wet to flooded pine flatwoods, savannas, bogs  +
Aletris obovata +Moist pine flatwoods and savannas, roadside ditches  +
Alisma gramineum +Shallow fresh or brackish water or muddy shores  +
Alisma lanceolatum +Streams and marshes  +
Alisma plantago-aquatica +Stream margins  +
Alisma subcordatum +Shallow ponds, stream margins, marshes, and ditches  +
Alisma triviale +Shallow muddy ponds, stream margins, marshes, and ditches  +
Allenrolfea occidentalis +Alkaline soils, mostly on raised sandy hummocks in salt playas and mud flats  +
Alliaria petiolata +Roadsides, trails, railroad tracks, stream banks, waste places, fields, shaded woodlands, bluffs, thickets, steep slopes, disturbed fields, floodplains, woods, shaded forest floor  +
Allionia choisyi +Open arid areas, often on sandy or gravelly soils, sometimes on clay or gypsum  +
Allionia incarnata var. incarnata +Open arid areas, usually on sandy or gravelly soils, sometimes on gypsum  +
Allionia incarnata var. villosa +Open arid areas, usually on sandy or gravelly soils, 100-1200 m  +
Allium aaseae +Coarse, sandy soil and gravelly river benches  +
Allium abramsii +Granite sands in open coniferous forest  +
Allium acuminatum +Dry slopes and plains  +
Allium ampeloprasum +Roadsides and other disturbed areas  +
Allium amplectens +Clay soils, including serpentine, dry slopes, and open plains  +
Allium anceps +Heavy, generally barren, clay soils  +
Allium atrorubens var. atrorubens +Sandy, rocky, or clay soils on desert slopes  +
Allium atrorubens var. cristatum +Sandy, rocky, or clay soils on desert slopes and mountains  +
Allium bigelovii +Open, rocky, gravelly slopes  +
Allium bisceptrum +Meadows and aspen groves, less commonly on open slopes in mountains  +
Allium bolanderi var. bolanderi +Clay soils, including serpentine  +
Allium bolanderi var. mirabile +Clay soils, including serpentine  +
Allium brandegeei +Sandy, rocky soil  +
Allium brevistylum +Swampy meadows and along streams, rarely on wooded slopes  +
Allium burlewii +Granite sands, on dry slopes and ridges  +
Allium campanulatum +Generally sandy soils on open or shaded slopes  +
Allium canadense var. canadense +Roadsides, meadows, woods, and fields  +
Allium canadense var. ecristatum +Known only from c coastal plain where it grows on prairies  +
Allium canadense var. fraseri +Generally in sandy or rocky soils, woods or plains  +
Allium canadense var. hyacinthoides +On calcareous prairies or more infrequently in sandy soils  +
Allium canadense var. lavendulare +Generally in calcareous soils  +
Allium canadense var. mobilense +Usually in sandy or rocky soils, rarely on limestone or in clay, woods and prairies  +
Allium cepa +Disturbed sites adjacent to areas where cultivated  +
Allium cernuum +Widely distributed on moist soils in mountainous and cool regions  +
Allium columbianum +Winter-wet, shallow soils on rock outcrops, or wet meadows  +
Allium constrictum +Shallow, lithosolic soils, often dry and sandy  +
Allium coryi +Rocky slopes and plains, mountains  +
Allium cratericola +Serpentine, volcanic, and granitic soil  +
Allium crenulatum +Talus slopes and clay soils, including serpentine, on bald summits and ridges  +
Allium crispum +Clay soils, including serpentine  +
Allium cuthbertii +On granitic “flat-rocks” of Piedmont and in sand on coastal plains  +
Allium denticulatum +Sandy, rocky soil, Techachapi Mountains and desert slopes, western Mojave Desert, California  +
Allium diabolense +Serpentine clay soils  +
Allium dichlamydeum +Dry, clay soils on or near sea cliffs  +
Allium dictuon +Rocky, sandy, basaltic soil  +
Allium douglasii +Winter-wet, shallow soils on rock outcrops  +
Allium drummondii +Plains, hills, and prairies, particularly in limestone soils  +
Allium elmendorfii +Sandy soil  +
Allium falcifolium +Heavy, rocky, clay soils, including serpentine  +
Allium fibrillum +Moist, shallow soils  +
Allium fimbriatum var. fimbriatum +Open clay (including serpentine) slopes and flats  +
Allium fimbriatum var. mohavense +Sandy or rocky soils on open slopes and flats  +
Allium fimbriatum var. purdyi +Serpentine clay  +
Allium fistulosum +Disturbed areas  +
Allium geyeri var. geyeri +Moist, open slopes, meadows, or stream banks in mountains  +
Allium geyeri var. tenerum +Meadows and along streams  +
Allium gooddingii +Steep, rocky slopes  +
Allium haematochiton +Dry slopes and ridges of clay or stony soil  +
Allium hickmanii +Grassy, wooded slopes and flats  +
Allium hoffmanii +Serpentine clay  +
Allium howellii var. clokeyi +Heavy clay soils, including serpentine  +
Allium howellii var. howellii +Clay soils, including serpentine, on open or grassy slopes  +
Allium howellii var. sanbenitense +Grassy slopes in heavy clay soils including serpentine  +
Allium hyalinum +Heavy, clay soils on shaded slopes  +
Allium jepsonii +Clay soils, including serpentine  +
Allium kunthii +Dry, rocky hills and mountains, usually in limestone soils  +
Allium lacunosum var. davisiae +Rocky, sandy, or clay soils  +
Allium lacunosum var. kernensis +Rocky, sandy, or clay soils  +
Allium lacunosum var. lacunosum +Apparently restricted to serpentine clays on ridges and peaks  +
Allium lacunosum var. micranthum +Rocky clay, including serpentine soils  +
Allium lemmonii +Drying, clay soils  +
Allium macropetalum +Desert plains and hills  +
Allium macrum +Barren, gravelly soils  +
Allium madidum +Seasonally wet meadows  +
Allium membranaceum +Wooded, shady slopes  +
Allium monticola +Loose rock and talus slopes, alpine ridges and talus  +
Allium munzii +Clay soil on grassy slopes  +
Allium neapolitanum +Disturbed sites  +
Allium nevadense +Sandy, rocky, or occasionally clay soils on desert plains and hillsides  +
Allium nevii +Heavy, rocky soils, wet meadows, or along streams  +
Allium nigrum +Disturbed roadsides  +
Allium obtusum var. conspicuum +Granitic sands  +
Allium obtusum var. obtusum +Granitic sands  +
Allium oleraceum +Roadsides and other disturbed ground  +
Allium paniculatum var. paniculatum +Disturbed areas  +
Allium parishii +Rocky, sandy desert slopes  +
Allium parryi +Clay or sandy soils on dry slopes  +
Allium parvum +Rocky, clay slopes and talus  +
Allium passeyi +Shallow, stony, lithosolic soil over dolomitic limestone, hilltops  +
Allium peninsulare var. franciscanum +Clay soil on dry hillsides  +
Allium peninsulare var. peninsulare +Clay soils, including serpentine  +
Allium perdulce var. perdulce +Usually sandy soils, plains  +
Allium perdulce var. sperryi +Rocky margins entire, apex obtuse or acute, slopes and plains  +
Allium platycaule +Rocky, sandy slopes  +
Allium plummerae +Rocky slopes, stream banks, and marshy ground, mountains  +
Allium praecox +Clay soil on shaded, grassy slopes near coast  +
Allium punctum +Sandy, rocky, or clay soils on open slopes and flats  +
Allium rhizomatum +Dry, usually grassy areas  +
Allium robinsonii +Sand and gravel deposits along bottom and lower benches of Columbia River  +
Allium rotundum +Disturbed fields and roadsides  +
Allium runyonii +Sandy soils, Rio Grande plains  +
Allium sanbornii var. congdonii +Heavy serpentine clay  +
Allium sanbornii var. sanbornii +Heavy serpentine clay  +
Allium sativum var. sativum +Roadsides and disturbed areas  +
Allium schoenoprasum +Wet meadows, rocky or gravelly stream banks and lake shores, circumboreal  +
Allium scilloides +Barren, gravelly soils, arid interior slopes and ridges well back from Columbia River  +
Allium serra +Heavy, clay soils, including serpentine  +
Allium sharsmithiae +Serpentine clay soil on talus slopes  +
Allium shevockii +Soil pockets on schist outcrops  +
Allium simillimum +Coarse, sandy soils of granitic, calcareous, or basaltic origins  +
Allium siskiyouense +Heavy, rocky, clay soils, including serpentine  +
Allium speculae +On gneiss “flat-rocks” and sandy soil of Piedmont  +
Allium stellatum +Often on calcareous soils  +
Allium textile +Dry plains and hills  +
Allium tolmiei var. persimile +Rocky, gravelly, or clay soils  +
Allium tolmiei var. tolmiei +Rocky, gravelly, or clay soils, mountains and scablands  +
Allium tribracteatum +Rocky, volcanic soils  +
Allium tricoccum var. burdickii +Dry soil in upland woods  +
Allium tricoccum var. tricoccum +Moist ground in rich woods, depressions, streamside bluffs, and colluvial slopes  +
Allium triquetrum +Disturbed sites  +
Allium tuberosum +Roadsides and other disturbed ground  +
Allium tuolumnense +Serpentine soil on open hillsides  +
Allium unifolium +Moist, clay soils, including serpentine, usually along streams  +
Allium validum +Swampy meadows in mountains  +
Allium victorialis +Rocky areas  +
Allium vineale +Disturbed areas often adjacent to agricultural lands  +
Allium yosemitense +Moist soil along cracks and margins of large metamorphic outcrops  +
Allotropa virgata +Moist, mixed-deciduous or coniferous forests  +
Allowissadula holosericea +Open habitats, roadsides  +
Allowissadula lozanoi +Mostly clay soil, open scrub or waste places  +
Almutaster pauciflorus +Damp alkaline places, alluvial soils, with halophytic vegetation, inland salt marshes, along streams in ravines, ditches, in desert and dry prairie areas  +
Alnus glutinosa +Stream banks, moist flood plains, damp depressions, borders of wetlands  +
Alnus incana subsp. rugosa +Stream banks, lake shores, bogs, swamps, margins of wet fields, swales, and roadsides, often forming dense thickets  +
Alnus incana subsp. tenuifolia +Stream banks, lake shores, margins of wet fields and meadows, bog margins, and muskegs  +
Alnus maritima +Along edges of ponds and small streams, often in standing water  +
Alnus oblongifolia +Sandy or rocky stream banks and moist slopes, often in mountain canyons  +
Alnus rhombifolia +Open, rocky stream banks and adjacent (often rather dry) slopes  +
Alnus rubra +Stream banks, moist flood plains, lake shores, wet slopes, and sandy, open coasts  +
Alnus serrulata +Stream banks, ditches, edges of sloughs, swampy fields and bogs, and lakeshores  +
Alnus viridis subsp. crispa +Singly or in thickets along streams, lakeshores, coasts, and bog or muskeg margins, or on sandy or gravelly slopes or flats  +
Alnus viridis subsp. fruticosa +Rocky or sandy coasts, stream banks, lakeshores, and damp, open areas  +
Alnus viridis subsp. sinuata +Along gravelly or rocky stream banks, lakeshores, and coasts, on moist rocky slopes, outcrops, in open coniferous woodlands  +
Aloe vera +Hammocks, sandy areas, roadsides, and similar places in full sun  +
Aloe ×schonlandii +Open sage scrub  +
Aloina aloides var. ambigua +Low, desert areas, banks and dry washes, soil and limestone  +
Aloina bifrons +Sunny sandy soil or soil over limestone in dry areas  +
Aloina brevirostris +Bare or disturbed soil or silt, roadside banks, calcareous boulders or gravel  +
Aloina hamulus +Sandstone or calcareous rocks, sandy soil in dry sunny sites  +
Aloina rigida var. rigida +Rocks, banks, clay, sandy or gravelly soil in deserts, plains or conifer forests  +
Alophia drummondii +Open woodlands, grassy pastures, often sandy soils  +
Alpinia zerumbet +Disturbed hammocks and thickets  +
Alsia californica +Bark of trunks and branches of Acer, Alnus, Chrysolepis, Lithocarpus, Quercus, Picea, Populus, Sambucus, Sequoia, Umbellularia, rock surfaces, usually siliceous  +
Alstroemeria pulchella +Loose or sandy soils in shade to partially sunny, moist, disturbed sites  +
Alternanthera brasiliana +Sandy, wet, disturbed sites  +
Alternanthera caracasana +Gravel, sand bars, sidewalks  +
Alternanthera ficoidea var. bettzickiana +Waste places  +
Alternanthera flavescens +Coastal hammocks, thickets, sand bars  +
Alternanthera maritima +Sandy beaches, hammocks  +
Alternanthera paronychioides +Ballast ground, swamps, sandy places, limestone near salt water  +
Alternanthera philoxeroides +Ponds, ditches, streams, bayous  +
Alternanthera pungens +Waste grounds, cleared limestone areas  +
Alternanthera sessilis +Wet disturbed areas  +
Althaea armeniaca +Wet or moist ditches, disturbed areas, stream drainages  +
Althaea cannabina +Disturbed, usually moist areas  +
Althaea hirsuta +Disturbed areas  +
Althaea officinalis +Wet, disturbed areas, along streams, brackish sand, coastal marshes  +
Alvaradoa amorphoides subsp. psilophylla +Hammocks, pine woodlands, on limestone  +
Alyssum alyssoides +Roadsides, railways, waste grounds, disturbed sites, grassy areas, fields, sagebrush flats, limestone ledges or bluffs  +
Alyssum desertorum +Deserts, rocky areas, disturbed sites, roadsides, fields, meadows, sagebrush flats  +
Alyssum murale +Waste areas, roadsides  +
Alyssum obovatum +Mountain slopes, cliffs, gravel, rocky places  +
Alyssum simplex +Sagebrush areas, fields, roadsides, sandy slopes  +
Alyssum szowitsianum +Rocky soil  +
Amaranthus acanthochiton +Sandy areas, sand dunes, riverbanks, disturbed habitats  +
Amaranthus albus +Disturbed habitats, waste places, vacant areas, railroads, streambanks, sandy areas, roadsides, agricultural fields  +
Amaranthus arenicola +Sandy habitats, sand hills, riverbanks, creeks, lakes, disturbed areas, agricultural fields  +
Amaranthus australis +Freshwater and brackish wetland habitats, coastal marshes, swamps, riverbanks, bayous, canals, ditches, estuaries, lakeshores, hammocks  +
Amaranthus blitoides +Disturbed habitats: roadsides, riverbanks, railroads, fields, waste places, sandy flats  +
Amaranthus blitum +Waste places, fields, roadsides, other disturbed habitats  +
Amaranthus californicus +Seasonally moist flats, shores of water bodies, waste places, other disturbed habitats  +
Amaranthus cannabinus +Coastal salt or brackish marshes, edges of sloughs, tidal riverbanks, tidal flats, rarely freshwater semiaquatic habitats  +
Amaranthus caudatus +Rarely occurs as escapes, persisting near the places of cultivation  +
Amaranthus crassipes +Open, seasonally wet flats, shores of water bodies, waste places, other disturbed habitats  +
Amaranthus crispus +Waste places, other disturbed habitats, mostly at seaports and on ballast  +
Amaranthus cruentus +Near places of cultivation  +
Amaranthus deflexus +Weedy areas, ballast heaps, railroads, other disturbed habitats  +
Amaranthus dubius +Waste places, disturbed habitats  +
Amaranthus fimbriatus +Sandy, gravelly slopes, washes, semideserts, disturbed habitats  +
Amaranthus floridanus +Coastal dunes, beaches, swamps, marshes, disturbed habitats, such as gardens and fields near coast  +
Amaranthus graecizans +On ballast  +
Amaranthus greggii +Coastal sand dunes, sea beaches  +
Amaranthus hybridus +Waste places, agricultural and fallow fields, railroads, roadsides, riverbanks, other disturbed habitats  +
Amaranthus hypochondriacus +Near places of cultivation  +
Amaranthus muricatus +Waste places, on ballast  +
Amaranthus obcordatus +Semideserts, naturally disturbed habitats  +
Amaranthus palmeri +Streambanks, disturbed habitats, especially agricultural fields, railroads, waste areas, roadsides  +
Amaranthus polygonoides +Disturbed habitats, coastal areas, near wool-combing mills  +
Amaranthus powellii +Disturbed habitats, agricultural fields, railroads, roadsides, waste areas, banks of rivers, lakes, and streams  +
Amaranthus pumilus +Maritime sand dunes, beaches, mostly on foredunes and at high tide level  +
Amaranthus retroflexus +Banks of rivers, lakes, and streams, disturbed habitats, agricultural fields, railroads, roadsides, waste areas  +
Amaranthus scleropoides +Seasonally wet, disturbed habitats  +
Amaranthus spinosus +Waste places, fields, roadsides, railroads, barnyards, overgrazed pastures, other disturbed habitats  +
Amaranthus tamaulipensis +Disturbed habitats  +
Amaranthus thunbergii +Uncommon, casual alien near wool-combing mills  +
Amaranthus torreyi +Sandy, rocky, and gravelly flats, slopes, canyons, washes, other naturally disturbed habitats  +
Amaranthus tricolor +Locally escaped from cultivation, disturbed areas  +
Amaranthus tuberculatus +Wet areas, such as margins of rivers, ponds, marshes, lakes, and creeks, disturbed habitats, such as agricultural fields, roadsides, and railroads  +
Amaranthus viridis +Fields, railroads, lawns, gardens, waste areas, other disturbed habitats  +
Amaranthus viscidulus +Open dry slopes, other naturally disturbed habitats  +
Amaranthus watsonii +Coastal dunes, beaches, sandy inland areas, weakly saline flats  +
Amaranthus wrightii +Naturally disturbed habitats, streambanks, canyons, semideserts  +
Amauriopsis dissecta +Usually on sandy or gravelly soils, openings in pinyon-juniper, yellow pine, or spruce-fir forests  +
Amberboa moschata +Escaped or persistent from cultivation in disturbed sites  +
Amblyodon dealbatus +Rotting wood, organic soil, rich fens scattered across boreal zone  +
Amblyolepis setigera +Roadsides, open fields  +
Amblyopappus pusillus +Coastal bluffs, dunes, beaches  +
Amblystegium serpens +Tree trunks, rotten wood, rock, soil, (sometimes salty) swamps to xeric habitats  +
Ambrosia acanthicarpa +Canyons, sandy flats, dunes  +
Ambrosia ambrosioides +Sandy soils, washes, banks  +
Ambrosia artemisiifolia +Wet to dry soils, disturbed sites  +
Ambrosia bidentata +Dry, disturbed sites  +
Ambrosia chamissonis +Sandy beaches and strand  +
Ambrosia cheiranthifolia +Seasonally wet clays or sands, scrublands  +
Ambrosia chenopodiifolia +Clays or sandy soils, among lava rocks  +
Ambrosia confertiflora +Waste places, disturbed sites  +
Ambrosia cordifolia +Sandy washes, benches  +
Ambrosia deltoidea +Sandy washes, benches  +
Ambrosia dumosa +Rocky or sandy washes, benches  +
Ambrosia eriocentra +Sandy and gravelly washes  +
Ambrosia grayi +Wet or seasonally wet flats, depressions, alkaline, clay soils, prairies  +
Ambrosia hispida +Sandy beaches or strand  +
Ambrosia ilicifolia +Sandy washes, benches  +
Ambrosia linearis +Seasonally wet, sandy soils  +
Ambrosia monogyra +Desert washes, ravines  +
Ambrosia psilostachya +Disturbed sites, often wet, alkaline, clay soils  +
Ambrosia pumila +Disturbed sites, damp to wet, alkaline soils  +
Ambrosia salsola +Desert washes, sandy and gravelly benches, lava talus  +
Ambrosia tomentosa +Seasonally wet clays or sands, disturbed sites  +
Ambrosia trifida +Disturbed sites, waste places, damp soils  +
Amelanchier alnifolia var. alnifolia +Stream banks and shores, lake shores, mountainsides, dry rocky and grassy slopes (northern shrub-steppe), hillsides, woods, thickets, shaded canyons, moist roadsides  +
Amelanchier alnifolia var. pumila +Mountain slopes  +
Amelanchier alnifolia var. semiintegrifolia +Woods, hillsides, roadsides, mountainsides  +
Amelanchier amabilis +Open woods, rocky banks, shores, calcareous sites  +
Amelanchier arborea +Dry to moist woods, mesic mixed hardwoods and pine-hardwoods, fields, thickets, roadsides, circumneutral soil, especially northward  +
Amelanchier bartramiana +Cool woods, mountain slopes, summits, bogs, poor fens, conifer swamps, acidic soil, sandy lake shores, stream banks, rocky ridges, roadside thickets  +
Amelanchier canadensis var. canadensis +Damp soil of swamps, wet streamheads, bogs, moist to wet thickets, woods  +
Amelanchier canadensis var. obovalis +Pine savannas, sandhills, roadsides, dry openings in woods, sandy soil  +
Amelanchier cusickii +Basaltic ledges, cliffs, and bluffs along streams, stony soil, streambeds, stream banks, copses, mountainsides, roadsides  +
Amelanchier fernaldii +Ravines, thickets, barrens, rocky banks, shores, sea cliffs, swamps, wet woods, often calcareous  +
Amelanchier gaspensis +Calcareous shores, gravel beaches, cliffs, ledges, alluvial woods, roadsides  +
Amelanchier humilis +Dry, open sites with rocky, gravelly, or sandy soil, calcareous soil  +
Amelanchier interior +Dry woods, bluffs rocky areas and slopes, stream banks, fields, thickets, and sandy areas, sometimes wetlands  +
Amelanchier intermedia +Swamps, bogs, thickets, shores  +
Amelanchier laevis +Dry to moist, deciduous, mixed, and coniferous forests, fields, thickets, roadsides  +
Amelanchier nantucketensis +Fields, sand-plain grasslands, heaths, glacial outwash plains, forest openings, disturbed sites, stream shores, among rocks or sand, dry habitats, ditches, swales  +
Amelanchier nitens +Dry rocky slopes, canyons, stream banks, mountainsides, foothills, high deserts  +
Amelanchier pallida +Dry rocky slopes, canyons, chaparral, mountainsides  +
Amelanchier sanguinea +Margins of woods, river ledges, shorelines, rocky slopes, crevices of open rock faces and cliffs, noncalcareous to slightly calcareous sites  +
Amelanchier spicata +Summits and cliffs of low mountains, open woods, woodland clearings, rocky soil, crevices, shores, fields, roadsides, peaty, sandy, or gravelly and, typically, acidic soil  +
Amelanchier utahensis +Dry rocky slopes, canyons, stream banks, mountainsides, foothills, deserts  +
Amerorchis rotundifolia +Moist, often calcareous coniferous forests, thickets, fens, tundra  +
Amianthium muscitoxicum +Dry or mesic wooded slopes, meadows, savannas  +
Amoreuxia gonzalezii +Limestone outcrops/hills, granitic talus slopes, deserts, cliffs, upper Sonoran desert scrub/grassland transition zone  +
Amoreuxia palmatifida +Gravelly, sometimes loamy, soil, dry rocky slopes and mesas, deserts, grasslands, openings in oak forests or secondary deciduous forests, disturbed sites, forest clearings and roadsides  +
Amoreuxia wrightii +Dry, rocky or gravelly hills, plains, deserts, grasslands, shrublands, along roads or railroads, limestone soil, silty flats  +
Ampelaster carolinianus +Marshy shores, stream banks, edges of swamps and moist thickets, wet woodlands  +
Ampelopsis aconitifolia +Thickets, forest edges.  +
Ampelopsis cordata +Stream and riverbanks, floodplain forests, wet woodland borders, lowland thickets, fencerows.  +
Ampelopsis glandulosa +Forest edges, pond margins, stream banks, thickets, disturbed areas.  +
Amphiachyris amoena +Calcareous soils and gravels on or near limestone outcrops  +
Amphiachyris dracunculoides +Calcareous, clay, or sandy soils, disturbed habitats  +
Amphidium californicum +Crevices of neutral to acidic rock  +
Amphidium lapponicum +Seasonal wet crevices of neutral to acidic cliffs  +
Amphidium mougeotii +Seasonally wet crevices of neutral to acidic cliffs  +
Amphipappus fremontii var. fremontii +Rocky or sandy soils, ravines, washes, slopes, rock outcrops, canyon walls, cliff faces, usually with other shrubs, especially Ambrosia, Yucca, Ephedra, Atriplex  +
Amphipappus fremontii var. spinosus +Rocky or sandy soils, flats, washes, slopes, rock outcrops, canyon walls, cliff faces, commonly with Larrea, Yucca, Ambrosia  +
Amphiscirpus nevadensis +Sunny, saline, often alkaline, seasonally wet places  +
Anacamptodon splachnoides +Bark of trees, wet, sheltered niches, crotches, fissures, knotholes on logs, stumps, sometimes rotten, wet rock  +
Anacolia laevisphaera +Dry to moist soil, rock crevices, talus slopes  +
Anacolia menziesii +Rock, ledges, ravines, shady canyons, soil  +
Anagallis arvensis +Open, disturbed sites  +
Anagallis minima +Moist to dry roadsides, disturbed meadows, forest edges, stream banks, swales  +
Anagallis monelli +Coastal sage scrub or dune swales  +
Anagallis pumila +Ditch banks, other open sites  +
Anaphalis margaritacea +Dry woods, often with aspen or mixed conifer-hardwood, borders and trails, dunes, fields, roadsides, other open, often disturbed sites  +
Ancistrocactus brevihamatus +Tamaulipan thorn scrub, Chihuahuan desert scrub, sparse grasslands, oak and juniper woodlands, creosotebush flats, sedimentary substrates including limestone [and gypsum in Mexico], usually not on steep slopes, rocky to gravelly soils  +
Ancistrocactus scheeri +Tamaulipan thorn scrub, plains and low hills, sandy, loamy, silty, or gravelly soils [rarely on shale]  +
Ancistrocarphus filagineus +Open, dry or vernally moist slopes, flats, drainages, shallow rocky to deep sandy or clay soils (often over serpentine or basalt), sometimes disturbed sites (burns, road beds)  +
Ancistrocarphus keilii +Sandy soils, chaparral bordering oak woodlands, under shrubs  +
Andreaea alpina +Wet acidic or basic rock  +
Andreaea blyttii +Rock, alluvium, edges of snow melt areas  +
Andreaea heinemannii +Acidic rocks  +
Andreaea megistospora +Acidic rock  +
Andreaea mutabilis +Acidic rock faces, occasionally thin soil  +
Andreaea nivalis +Wet rocks in streams, snow flushes, seeping outcrops  +
Andreaea obovata +Rock or soil in streams  +
Andreaea rothii +Siliceous rock, cliffs, boulders  +
Andreaea rupestris +Neutral to acidic boulders, cliffs and walls, generally wet sites  +
Andreaea schofieldiana +Dry rock outcrops  +
Andreaea sinuosa +Acidic rock in snow beds  +
Andreaeobryum macrosporum +Calcareous rock in Arctic and subarctic areas  +
Andromeda polifolia var. latifolia +Open, wet sites, bogs, fens, margins of pools, along boggy shores  +
Andromeda polifolia var. polifolia +Sphagnum peat bogs, acid swamps, margins of pools throughout boreal forest and arctic  +
Androsace chamaejasme subsp. lehmanniana +Rocky, open habitats on tundra  +
Androsace elongata subsp. acuta +Open, grassy slopes  +
Androsace filiformis +Wet meadows  +
Androsace occidentalis +Open, grassy meadows, sandy or gravelly open soils, often in disturbed areas  +
Androsace septentrionalis +Open areas with sandy, gravelly soil in grassland, shrub, forest, and tundra communities  +
Androstephium breviflorum +Desert, arid scrub, dry sandy to rocky soil  +
Androstephium coeruleum +Prairies, grassy slopes, frequently in rocky areas  +
Anelsonia eurycarpa +Rock slides of metamorphics, whitish ash, subalpine and alpine ridges, rock and talus slides, disintegrated volcanic rock  +
Anemia adiantifolia +Terrestrial on open to lightly shaded, rocky slopes and in hammocks and pine woods, often on limestone  +
Anemia mexicana +Lightly shaded limestone outcrops of the Edwards Plateau  +
Anemia wrightii +Rare around exposed to lightly shaded solution holes and limestone sinks  +
Anemone acutiloba +Deciduous woods, often in calcareous soils  +
Anemone americana +Mixed woods, often in association with both conifers and deciduous trees  +
Anemone berlandieri +Open grasslands, prairies, hillsides, often limy substrate, also woods over thin shale  +
Anemone canadensis +Damp thickets, meadows, wet prairies, lake shores, streamsides, clearings, occasionally swampy areas  +
Anemone caroliniana +Dry prairies, barrens, pastures, meadows, rocky, open woods  +
Anemone cylindrica +Prairies, dry, open woods, pastures, roadsides  +
Anemone deltoidea +Open to deep woods  +
Anemone drummondii var. drummondii +Gravelly slopes, dry rocky ledges  +
Anemone drummondii var. lithophila +Slopes, ridges  +
Anemone edwardsiana var. edwardsiana +Moist, limestone bluffs and ledges  +
Anemone edwardsiana var. petraea +Moist, rocky crevices  +
Anemone grayi +Shaded woods, wooded slopes  +
Anemone lancifolia +Damp, rich woods  +
Anemone lyallii +Shaded woods, subalpine ridges  +
Anemone multiceps +Tundra, slopes, ridges, limestone outcrops, and screes  +
Anemone multifida var. multifida +Open forests, grassy slopes, often rocky areas, also moist prairie depressions, coulees, sandhill shrubland  +
Anemone multifida var. saxicola +Rocky slopes, meadows  +
Anemone multifida var. stylosa +Rocky slopes  +
Anemone multifida var. tetonensis +Talus slopes, canyons  +
Anemone narcissiflora var. monantha +Moist slopes, grassy areas, thickets  +
Anemone narcissiflora var. villosissima +Meadows, tundra  +
Anemone narcissiflora var. zephyra +Forest margins, alpine meadows  +
Anemone occidentalis +Gravelly, rocky slopes, moist meadows  +
Anemone okennonii +Dry, open ledges and slopes  +
Anemone oregana var. felix +Marshes, sphagnum bogs  +
Anemone oregana var. oregana +Shaded, moist woods, open hillsides  +
Anemone parviflora +Streamsides, meadows, rocky slopes  +
Anemone patens var. multifida +Prairies, open slopes, sometimes open woods or granite outcrops in woods  +
Anemone piperi +Shaded, moist woods  +
Anemone quinquefolia var. minima +Damp, frequently acidic, wooded hillsides  +
Anemone quinquefolia var. quinquefolia +Moist, open woods, thickets, clearings, streamsides, occasionally swampy areas  +
Anemone richardsonii +Thickets, moist woods, meadows, slopes  +
Anemone tuberosa +Rocky slopes, streamsides  +
Anemone virginiana var. alba +Riparian areas, moist cliffs and ledges  +
Anemone virginiana var. cylindroidea +Dry woods, sandy ridges, grasslands  +
Anemone virginiana var. virginiana +Dry, rocky, open woods, thickets, river banks  +
Anemopsis californica +Wet, alkaline, saline, and coastal marsh areas  +
Angelonia gardneri +Roadsides, disturbed ground.  +
Anisocarpus madioides +Forests, woodlands  +
Anisocarpus scabridus +Open ridges and slopes, on metamorphics  +
Anisocoma acaulis +Sandy washes, dry slopes, chaparral, pine-oak-juniper woodlands, montane coniferous forests  +
Annona glabra +Wet substrates, brackish to fresh, in pond borders, tidally influenced stream banks, banks of estuaries and lakes  +
Annona squamosa +Dryish sandy substrates, dry hammocks  +
Anoda abutiloides +Dry, open shrublands  +
Anoda crenatiflora +Dry, open shrublands, deciduous forests  +
Anoda cristata +Usually weedy in disturbed areas, fence rows, agricultural fields  +
Anoda lanceolata +Arid habitats, disturbed sites, sometimes open, sometimes shady  +
Anoda pentaschista +Disturbed sites, roadsides, agricultural fields  +
Anoda reticulata +Desert habitats  +
Anoda thurberi +Deciduous forests, dry, open shrublands  +
Anoectangium aestivum +Forming deep green cushions on calcareous and noncalcareous rock, sandstone walls, rock ledges, exposed moist crevices, wet areas  +
Anoectangium handelii +Fissures in rock, calcareous and noncalcareous sandstone  +
Anoectangium stracheyanum +Calcareous and noncalcareus rock, wet areas, spray of falls  +
Anomobryum concinnatum +Acidic seepy or damp soil, soil over rock, ledges  +
Anomobryum julaceum +Acidic seepy or damp soil, soil over rock, ledges  +
Anomodon attenuatus +Tree bark, at base, soil, rock  +
Anomodon longifolius +Crevices between boulders  +
Anomodon minor +Deciduous forests, calcareous rock, bark of trees  +
Anomodon rostratus +Base or bark of deciduous trees, soil, fallen logs, deciduous forests, open spaces, secondary forests, vertical calcareous rock, occasionally acidic  +
Anomodon rugelii +Tree trunks (generally 1-2 m above base), basic and acidic rock, montane deciduous forests  +
Anomodon thraustus +Bark of trees, deciduous forests  +
Anomodon tristis +Bark of trees, deciduous forests  +
Anomodon viticulosus +Mesic calcareous environments of montane deciduous forests, limestone rock or vertical walls, epiphytic  +
Anredera cordifolia +Disturbed areas, fencerows, roadsides  +
Anredera vesicaria +Disturbed areas, fencerows, roadsides, thickets  +
Antennaria alpina +Dry to moist alpine tundra  +
Antennaria anaphaloides +Dry meadows and aspen forest openings  +
Antennaria arcuata +Moist alkaline basins in sagebrush steppe  +
Antennaria argentea +Openings in dry coniferous forests  +
Antennaria aromatica +Subalpine limestone talus  +
Antennaria corymbosa +Moist subalpine-alpine willow thickets in the Rocky and Cascade mountains, the Sierra Nevada and mountains of the Great Basin  +
Antennaria densifolia +Subalpine-alpine limestone talus  +
Antennaria dimorpha +Sagebrush steppe, plains, foothills of mountains  +
Antennaria dioica +Dry slopes on tundra  +
Antennaria flagellaris +Seasonally dry basins in foothills of mountains, often associated with sagebrush flats  +
Antennaria friesiana subsp. alaskana +Arctic and alpine tundra, on or near dry rocky outcrops or sand ridges  +
Antennaria friesiana subsp. friesiana +Arctic and alpine tundra, on or near dry rocky outcrops or sand ridges  +
Antennaria friesiana subsp. neoalaskana +Arctic and alpine tundra, on dry rocky outcrops, fell fields, or gravelly frost boils  +
Antennaria geyeri +Dry lower montane to montane coniferous forests, usually in ± thick duff under Pinus ponderosa  +
Antennaria howellii subsp. canadensis +Pastures, dry fields, openings in woodlands and forests, and rock barrens  +
Antennaria howellii subsp. howellii +Pastures, dry fields, openings in deciduous woodlands and coniferous forests. and rock barrens  +
Antennaria howellii subsp. neodioica +Pastures, dry fields, openings in woodlands and forests, and rock barrens and dry lake shores  +
Antennaria howellii subsp. petaloidea +Pastures, dry fields, openings in woodlands and forests, and rock barrens  +
Antennaria lanata +Protected alpine and subalpine sites, gravelly or sandy soils near conifers at timberline  +
Antennaria luzuloides subsp. aberrans +Moist, open, meadows and drainages, lower montane, ponderosa pine zone  +
Antennaria luzuloides subsp. luzuloides +Semidry meadows and drainages, lower montane, ponderosa pine zone  +
Antennaria marginata +Moist forests, slopes and tops of ridges under Douglas fir, ponderosa pine, Engelmann spruce or Gambel oaks, openings in the forests  +
Antennaria media +Dry, rocky to moist alpine tundra  +
Antennaria microphylla +Moist open areas, flood plains of streams, margins of alkaline depressions, lower montane to subalpine (subarctic)  +
Antennaria monocephala subsp. angustata +Moist tundra, disturbed margins of solifluction lobes, unstable, gravelly slopes  +
Antennaria monocephala subsp. monocephala +Moist tundra, often on disturbed margins of solifluction lobes or on unstable, gravelly slopes  +
Antennaria neglecta +Plains, grasslands, pastures, and open woodlands  +
Antennaria parlinii subsp. fallax +Clearings, fields, roadsides, and open deciduous woods  +
Antennaria parlinii subsp. parlinii +Clearings, fields, roadsides, and open woods  +
Antennaria parvifolia +Prairies, pastures, roadsides, mountain parks, open deciduous woods, and drier coniferous forests, usually ponderosa or lodgepole pine  +
Antennaria plantaginifolia +Dry, open, deciduous woodlands, tops of banks, ridges, and bluffs, sandstone formations, slopes in openings in woodlands  +
Antennaria pulchella +Moist subalpine-alpine meadows, snow basins, margins of tarns, streams, or run-off from snow masses  +
Antennaria pulcherrima subsp. eucosma +Limestone barrens, serpentine  +
Antennaria pulcherrima subsp. pulcherrima +Alluvial soils in moist willow thickets subject to intermittent flooding along streams, montane to subalpine zone  +
Antennaria racemosa +Moist, cool, montane and subalpine coniferous forests and roadcuts in forests  +
Antennaria rosea subsp. arida +Dry to moist habitats, tundra, rock outcrops, fields, meadows, forests, savannas, and roadcuts, other similarly disturbed places  +
Antennaria rosea subsp. confinis +Dry to moist habitats, tundra, rock outcrops, fields, meadows, forests, savannas, and roadcuts, other similarly disturbed places  +
Antennaria rosea subsp. pulvinata +Dry to moist open habitats, usually on rock outcrops or barrens  +
Antennaria rosea subsp. rosea +Dry to moist habitats, tundra, rock outcrops, fields, meadows, forests, savannas, and roadcuts, other similarly disturbed places  +
Antennaria rosulata +Open slopes and dry meadows, lower montane to montane, or subalpine zone, usually with big sagebrush, Artemisia tridentata  +
Antennaria soliceps +Talus areas on limestone ridge at treeline in the subalpine zone  +
Antennaria solitaria +Slopes or stream banks in moist, rich, deciduous woodlands, forests, sometimes forest openings  +
Antennaria stenophylla +Dry, often sagebrush (Artemisia) covered hillsides and dry margins around seasonally moist depressions in sagebrush steppe of the Great Basin and Columbia Plateau  +
Antennaria suffrutescens +Dry, open coniferous woods or barren slopes on serpentine  +
Antennaria umbrinella +Sagebrush steppe to open, dry, coniferous montane forests to subalpine meadows  +
Antennaria virginica +Devonian shale barrens and argillaceous soils derived from them, open deciduous woods and fields  +
Anthemis arvensis +Disturbed sites, abandoned plantings  +
Anthemis cotula +Disturbed sites, clearings, fields, roadsides  +
Antigonon leptopus +Cultivated and often persisting after abandonment, rarely escaping  +
Antirrhinum majus +Disturbed ground.  +
Antitrichia californica +Bark, decorticated wood, on Quercus, siliceous rock, soil, humic soil, full sun or partial shade  +
Antitrichia curtipendula +Trunks and branches of Acer, Alnus, Populus, Prunus, Quercus, conifers, dead branches, snags, decorticated or decomposing logs, siliceous rock, soil, humus  +
Anulocaulis annulatus +Dry, gravelly outwash fans, talus slopes, roadsides  +
Anulocaulis eriosolenus +Sandy, gravelly limestone outwash fans, or calcareous silty soils, gypsum  +
Anulocaulis leiosolenus var. gypsogenus +Gypsum outcrops  +
Anulocaulis leiosolenus var. howardii +Gypsum outcrops  +
Anulocaulis leiosolenus var. lasianthus +Calcareous clay and clayey shales  +
Anulocaulis leiosolenus var. leiosolenus +Calcareous clays and shales, sometimes on gypsum  +
Anulocaulis reflexus +Gypseous shaley clay  +
Aongstroemia longipes +Moist, exposed, sandy or silty soil of depressions, river and stream banks in montane coniferous forest regions, subalpine regions, mountains, and northern latitudes  +
Apacheria chiricahuensis +Rock crevices, cliff faces, on igneous or volcanic substrates (mostly rhyolite)  +
Aphanes arvensis +Fields, usually on sandy soil, mossy and grassy sites, moist shade, gravelly roadsides, shady, bare patches in lawns, shallow soil pockets on rocky seashores, meadows, hillsides  +
Aphanes australis +Fields, sandy places  +
Aphanes occidentalis +Vernally moist grasslands, chaparral, woodlands, clearings, rocky outcrops, cliffs, sandy beaches, waste ground, roadsides  +
Aphanisma blitoides +Coastal shrublands, bluffs, saline sands  +
Aphanorrhegma serratum +Soil, clay, along creeks or trails in places subject to inundation, rarely among other mosses  +
Aphanostephus pilosus +Sand or sandy clay, open scrub oak woodlands, mesquite savannas, fields, disturbed sites, roadsides  +
Aphanostephus ramosissimus var. humilis +Sand and gravel bars, limestone soils, Larrea flats, mesquite savannas, roadsides, disturbed sites  +
Aphanostephus ramosissimus var. ramosissimus +Sand and sandy loam, black loam, silt, caliche, rocky limestone soils, stream bottoms, oak-juniper openings, mesquite pastures, roadsides, fencerows, disturbed sites  +
Aphanostephus riddellii +Open sites, often calcareous, often with scrubby oaks  +
Aphanostephus skirrhobasis var. kidderi +Sandy or gravelly soils, often in matorral and scrublands  +
Aphanostephus skirrhobasis var. skirrhobasis +Sand, sandy loam, sandy clay, silt, gravel, river terraces, oak woodlands, mesquite savannas, fields, roadsides  +
Aphanostephus skirrhobasis var. thalassius +Sand dunes near beaches, coastal sands, Rio Grande plains  +
Aphragmus eschscholtzianus +Limestone slopes, subalpine valleys, wet cliffs, ridges, fine gravel saturated by snowmelt  +
Aplectrum hyemale +Moist, deciduous, upland to swampy forests  +
Aplodon wormskioldii +Dung, animal remains  +
Apodanthera undulata var. undulata +Roadsides, gravelly stream terraces, interfan alluvium, dunes, flats, rocky slopes, lava beds, grasslands, creosote scrub, Chihuahuan desert scrub of Flourensia-Larrea, mesquite, oak chaparral, oak-juniper woodlands  +
Aponogeton distachyos +Quiet ponds  +
Aptenia cordifolia +Disturbed places, coastal bluffs, margins of coastal wetlands, 0-100 m  +
Apteria aphylla +Bogs, alluvial and upland rich woods  +
Aquilegia barnebyi +Cliff walls and talus slopes, usually on shale  +
Aquilegia brevistyla +Open woods, meadows, shores, and rock outcrops  +
Aquilegia canadensis +Shaded or open woods, often around cliffs, rock outcrops, and forest edges  +
Aquilegia chaplinei +Rocky places in canyons, mostly along streams  +
Aquilegia chrysantha +Damp places in canyons  +
Aquilegia coerulea var. alpina +Open rocky slopes  +
Aquilegia coerulea var. coerulea +Rocky slopes or near streams in open woodland or herbland  +
Aquilegia coerulea var. ochroleuca +Rocky slopes or near streams, in open woodland or herbland  +
Aquilegia coerulea var. pinetorum +Rocky slopes or near streams, in open woodland or herbland  +
Aquilegia desertorum +Open rocky places  +
Aquilegia elegantula +Moist coniferous forests, especially along streams  +
Aquilegia eximia +Damp rocky places  +
Aquilegia flavescens +Moist mountain meadows and alpine slopes  +
Aquilegia formosa var. formosa +Mesic woods  +
Aquilegia formosa var. hypolasia +Mesic woods or shrublands  +
Aquilegia formosa var. truncata +Mesic woods or shrublands  +
Aquilegia hinckleyana +Dripping cliffs  +
Aquilegia jonesii +Rocky places in limestone areas, usually subalpine  +
Aquilegia laramiensis +Rock crevices  +
Aquilegia longissima +Near streams or in damp rocky places in canyons  +
Aquilegia micrantha +Seepy rock walls of canyons  +
Aquilegia pubescens +Open rocky places, alpine or subalpine  +
Aquilegia saximontana +Cliffs and rocky slopes, subalpine and alpine  +
Aquilegia scopulorum +Rocky slopes, woodlands, or meadows  +
Aquilegia shockleyi +Moist places in dry woodlands and shrublands  +
Aquilegia vulgaris +Disturbed habitats  +
Arabidopsis arenicola +Sandy beaches, gravel, flats of streambeds  +
Arabidopsis arenosa subsp. arenosa +Above fjords  +
Arabidopsis lyrata subsp. kamchatica +Gravelly slopes, forests, gravel bars, high-elevation scree and talus, roadsides  +
Arabidopsis lyrata subsp. lyrata +Cliffs, ledges, thickets, stream and river banks, woods, limestone crevices and bluffs, sandstone hills and outcrops, serpentine rocks and barrens, shale, talus, sand dunes  +
Arabidopsis lyrata subsp. petraea +Sand dunes, sand bars, tussocks, gravel, tundra, volcanic ash, stream terraces  +
Arabidopsis thaliana +Sandy areas along roadsides, stream banks, railroad tracks and embankments, open pastures, grassy flats, fields, prairies, floodplains, woods, lawns, limestone ledges and crevices, bluffs, shale and serpentine barrens, gravel, sandstone  +
Arabis aculeolata +Serpentine slopes, rocky hillsides  +
Arabis alpina +Crevices of limestone rocks, along streams, calcareous alpine meadows, Salix scrub on slopes with scree  +
Arabis blepharophylla +Rocky hillsides and bluffs, grassy hillsides, slopes  +
Arabis caucasica +Rare garden escape  +
Arabis crucisetosa +Open woods, rocky bluffs, steep banks, canyon margins  +
Arabis eschscholtziana +Rocky slopes, crevices, and ledges, meadows, moist banks and grounds, granitic soil, wooded slopes  +
Arabis furcata +Open slopes, alpine meadows, cliffs, ridge crests  +
Arabis georgiana +Stream banks, roadsides  +
Arabis mcdonaldiana +Serpentine scrap and slopes, red serpentinized soil  +
Arabis modesta +Moist shaded banks, slopes, rocky canyon walls, talus, basaltic bluffs  +
Arabis nuttallii +Alpine and subalpine meadows and slopes, open woods, steep slopes and cliffs, mossy mats, dry or moist slopes and hillsides, ridge crests  +
Arabis olympica +Talus slopes near glacier  +
Arabis oregana +Moist granitic soil, rocky hillsides, chaparrals, steep banks  +
Arabis patens +Rocky wooded slopes, shady stream banks, limestone ledges and bluffs  +
Arabis pycnocarpa var. adpressipilis +Ravines, pastures, cliffs, calcareous talus, dolomite glades, rich woods, bluffs, rocky ledges  +
Arabis pycnocarpa var. pycnocarpa +Bluffs, cliffs, ledges, rocky hillsides, open woods, bottom lands, gravel bars, meadows, streamsides, upland prairies, grassy swales, hillsides, stream bottoms  +
Arachniodes simplicior +Terrestrial along stream banks in woods  +
Arbutus arizonica +Riverine forests and oak parklands along seasonally moist waterways  +
Arbutus menziesii +Open forests, rocky slopes, ravines, foothills, and shores  +
Arbutus xalapensis +Rough, stony hills, mountain slopes, calcareous ledges  +
Arceuthobium americanum +Coniferous forests, especially with jack or lodgepole pine.  +
Arceuthobium campylopodum subsp. abietinum +Coniferous forests generally with fir.  +
Arceuthobium campylopodum subsp. apachecum +Coniferous forests with southwestern white pine.  +
Arceuthobium campylopodum subsp. blumeri +Coniferous forests with southwestern white pine.  +
Arceuthobium campylopodum subsp. californicum +Coniferous forests with sugar pine or western white pine.  +
Arceuthobium campylopodum subsp. campylopodum +Coniferous forests with ponderosa or Jeffrey pine.  +
Arceuthobium campylopodum subsp. cyanocarpum +Coniferous forests.  +
Arceuthobium campylopodum subsp. laricis +Coniferous forests, especially with western larch or mountain hemlock.  +
Arceuthobium campylopodum subsp. littorum +Closed-cone pine forests.  +
Arceuthobium campylopodum subsp. microcarpum +Coniferous forests, especially with blue or Engelmann spruce.  +
Arceuthobium campylopodum subsp. monticola +Coniferous forests, especially with western white pine.  +
Arceuthobium campylopodum subsp. occidentale +Coniferous and mixed forests, especially with digger pine.  +
Arceuthobium campylopodum subsp. siskiyouense +Coniferous forests, especially closed-cone pine forests with knobcone pine.  +
Arceuthobium campylopodum subsp. tsugense +Coniferous forests.  +
Arceuthobium divaricatum +Pinyon-juniper woodlands.  +
Arceuthobium douglasii +Coniferous forests with Douglas fir.  +
Arceuthobium gillii +Coniferous and mixed forests with Chihuahua pine.  +
Arceuthobium pusillum +Spruce forests within 500 m of coast and inland bogs, often within 2 km of lakes and rivers.  +
Arceuthobium vaginatum subsp. cryptopodum +Coniferous forests with ponderosa pine.  +
Archidium alternifolium +Common on moist to wet soil, mud and sand around temporary pools, along ditches and roadsides, and in fields, occasional on sandstone and limestone outcrops  +
Archidium donnellii +Uncommon on moist to dry soil along roadsides, in fields, rarely on rock  +
Archidium hallii +Uncommon to rare on moist open sandy or loamy soil, along roadsides and in grassy often disturbed areas  +
Archidium minus +Uncommon on moist open sandy or loamy soil, along roadsides and in grassy often disturbed areas, or crevices and pockets in rock  +
Archidium ohioense +Common on moist open sandy, loamy, or clay soils, mud, and rock outcrops in a wide variety of open habitats, including roadsides, ditches, meadows, prairies, sand dunes, and creeks  +
Archidium tenerrimum +Common to uncommon on dry to moist sand, soil, in clearings, along roadsides, creek banks, open forests, pastures, often on soil of limestone and sandstone outcrops  +
Arctanthemum arcticum subsp. arcticum +Open, coastal, wet, brackish habitats on clay, sand, gravel or rocks, upper tidal marshes, brackish coastal meadows, coastal herbaceous or heath tundras, sloughs, coastal rocks, flood plains and bars at mouths of streams  +
Arctanthemum arcticum subsp. polare +Open, coastal, wet, brackish habitats on clay, sand, gravel, or rocks, beaches near tideline, coastal dunes, beach meadows, carex salt marshes, estuarine marshes and flood plains, coastal tundra  +
Arctium lappa +Waste places, roadsides, fields, forest clearings  +
Arctium minus +Waste places, roadsides, fields, forest clearings  +
Arctium tomentosum +Waste places, roadsides, fields, forest clearings  +
Arctoa anderssonii +Siliceous rock  +
Arctoa fulvella +Siliceous rock or soil  +
Arctoa hyperborea +Siliceous rock or soil  +
Arctomecon californica +Barren shales that are heavily gypsiferous or otherwise chemically unusual (borate-bearing, lithium-bearing), creosote bush zone  +
Arctomecon humilis +Barren, heavily gypsiferous shales, creosote bush zone  +
Arctomecon merriamii +Barren, calcareous, scree slopes and weakly gypsiferous shales interbedded with marine limestones, creosote bush and blackbrush zones  +
Arctostaphylos andersonii +Chaparral, edges of open forests  +
Arctostaphylos auriculata +Chaparral, open, closed-cone conifer forests  +
Arctostaphylos bakeri subsp. bakeri +Closed-cone conifer chaparral on serpentine soil  +
Arctostaphylos bakeri subsp. sublaevis +Closed-cone conifer chaparral on serpentine soil  +
Arctostaphylos canescens subsp. canescens +Chaparral, open forests  +
Arctostaphylos canescens subsp. sonomensis +Chaparral, open forests  +
Arctostaphylos catalinae +Chaparral, open woodlands  +
Arctostaphylos columbiana +Chaparral, gaps and margins of conifer forests along coast, sometimes extending inland, open areas around rock outcrops  +
Arctostaphylos confertiflora +Island chaparral, open, closed-cone conifer forests  +
Arctostaphylos crustacea subsp. crinita +Maritime chaparral and open conifer forests  +
Arctostaphylos crustacea subsp. crustacea +Maritime and marginal interior chaparral and closed-cone conifer forests  +
Arctostaphylos crustacea subsp. eastwoodiana +Maritime chaparral and closed-cone conifer forests on siliceous shales  +
Arctostaphylos crustacea subsp. insulicola +Maritime chaparral on volcanic soils  +
Arctostaphylos crustacea subsp. rosei +Maritime chaparral and coastal bluffs, historic stable dunes  +
Arctostaphylos crustacea subsp. subcordata +Island chaparral  +
Arctostaphylos cruzensis +Maritime chaparral, grasslands on alluvial and fluvial soils  +
Arctostaphylos densiflora +Acidic marine sands  +
Arctostaphylos edmundsii +Steep, rocky slopes and bluffs near ocean  +
Arctostaphylos franciscana +Maritime chaparral, serpentine soils  +
Arctostaphylos gabilanensis +Chaparral on decomposing granites  +
Arctostaphylos glandulosa subsp. adamsii +Interior chaparral chiefly on granitic rocks  +
Arctostaphylos glandulosa subsp. crassifolia +Maritime chaparral and closed-cone conifer forests on sandstone coastal bluffs  +
Arctostaphylos glandulosa subsp. cushingiana +Pure and mixed chaparral  +
Arctostaphylos glandulosa subsp. gabrielensis +Chaparral  +
Arctostaphylos glandulosa subsp. glandulosa +Chaparral, often on steep, rocky slopes  +
Arctostaphylos glandulosa subsp. howellii +Chaparral  +
Arctostaphylos glandulosa subsp. leucophylla +interior chaparral on gabbroic soils  +
Arctostaphylos glandulosa subsp. mollis +interior chaparral  +
Arctostaphylos glauca +Rocky slopes, chaparral, woodlands  +
Arctostaphylos glutinosa +Chaparral, closed-cone conifer forests  +
Arctostaphylos hispidula +Serpentine chaparral and open forests on sandstone  +
Arctostaphylos hookeri subsp. hearstiorum +Coastal prairies  +
Arctostaphylos hookeri subsp. hookeri +Maritime chaparral and closed-cone conifer forests on stable dunes and sandstone uplands  +
Arctostaphylos hooveri +Chaparral, open conifer forests  +
Arctostaphylos imbricata +Maritime chaparral on sandstone outcroppings  +
Arctostaphylos insularis +Island chaparral and woodlands  +
Arctostaphylos klamathensis +Open, subalpine forests on soils derived from gabbro  +
Arctostaphylos luciana +Chaparral  +
Arctostaphylos malloryi +Chaparral, open forests  +
Arctostaphylos manzanita subsp. elegans +Chaparral, upper foothill woodlands  +
Arctostaphylos manzanita subsp. glaucescens +Chaparral, foothill woodlands  +
Arctostaphylos manzanita subsp. laevigata +Chaparral, foothill woodlands  +
Arctostaphylos manzanita subsp. manzanita +Foothill woodlands, interior chaparral, sometimes in open conifer forests  +
Arctostaphylos manzanita subsp. roofii +Chaparral  +
Arctostaphylos manzanita subsp. wieslanderi +Upper foothill woodlands, open conifer forests  +
Arctostaphylos mewukka subsp. mewukka +Chaparral or along forest edges, often along ridge crests  +
Arctostaphylos mewukka subsp. truei +Chaparral openings in mixed conifer forests  +
Arctostaphylos montana subsp. montana +Chaparral on upland serpentine barrens  +
Arctostaphylos montana subsp. ravenii +Maritime chaparral, coastal prairie on serpentine soils  +
Arctostaphylos montaraensis +Maritime chaparral  +
Arctostaphylos montereyensis +Maritime chaparral  +
Arctostaphylos morroensis +Maritime chaparral on sandy soils near coast  +
Arctostaphylos myrtifolia +Exposed acidic, whitish, clay soils (oxisols)  +
Arctostaphylos nevadensis subsp. knightii +High-elevation forests and montane chaparral  +
Arctostaphylos nevadensis subsp. nevadensis +High-elevation forests and montane chaparral  +
Arctostaphylos nissenana +Shallow shale soils in chaparral and foothill woodlands  +
Arctostaphylos nortensis +Chaparral, open forests  +
Arctostaphylos nummularia subsp. mendocinoensis +Podsol soils in pygmy pine forests  +
Arctostaphylos nummularia subsp. nummularia +Maritime chaparral, closed-cone conifer forests  +
Arctostaphylos obispoensis +Chaparral, open, closed-cone conifer forests  +
Arctostaphylos ohloneana +Knobcone pine chaparral, siliceous shale ridges  +
Arctostaphylos osoensis +Maritime chaparral on volcanic uplands  +
Arctostaphylos otayensis +Chaparral  +
Arctostaphylos pacifica +Sandstone outcrops  +
Arctostaphylos pajaroensis +Maritime chaparral on deep to shallow, sandy soils or sandstone outcroppings  +
Arctostaphylos pallida +Maritime chaparral, gaps in open forests  +
Arctostaphylos parryana subsp. desertica +Chaparral on desert edges  +
Arctostaphylos parryana subsp. parryana +Montane chaparral and forest openings  +
Arctostaphylos parryana subsp. tumescens +Montane chaparral  +
Arctostaphylos patula +Mountain chaparral and forests  +
Arctostaphylos pechoensis +Maritime chaparral on siliceous shale soils  +
Arctostaphylos pilosula +Chaparral, open forests  +
Arctostaphylos pringlei subsp. drupacea +Chaparral, open forests  +
Arctostaphylos pringlei subsp. pringlei +Chaparral, open forests  +
Arctostaphylos pumila +Sand dunes, maritime chaparral, open, closed-cone conifer forests  +
Arctostaphylos pungens +Open pine forests, pinyon-juniper woodlands, chaparral  +
Arctostaphylos purissima +Maritime chaparral on deep, sandy soils  +
Arctostaphylos rainbowensis +Chaparral of granite uplands  +
Arctostaphylos refugioensis +Chaparral  +
Arctostaphylos regismontana +Chaparral, margins of open forests  +
Arctostaphylos rudis +Maritime chaparral on sandy soils  +
Arctostaphylos sensitiva +Sandstone uplands in maritime chaparral or closed-cone conifer forests near coast  +
Arctostaphylos silvicola +Chaparral, open conifer forests  +
Arctostaphylos stanfordiana subsp. decumbens +Chaparral, clay barrens  +
Arctostaphylos stanfordiana subsp. raichei +Chaparral, on or near serpentine  +
Arctostaphylos stanfordiana subsp. stanfordiana +Chaparral  +
Arctostaphylos tomentosa subsp. bracteosa +Maritime chaparral in stabilized dunes or on coastal uplands  +
Arctostaphylos tomentosa subsp. daciticola +Maritime chaparral on dacite buttes  +
Arctostaphylos tomentosa subsp. hebeclada +Maritime chaparral on coastal uplands  +
Arctostaphylos tomentosa subsp. tomentosa +Maritime chaparral on stabilized dunes or coastal uplands  +
Arctostaphylos uva-ursi +Coastal dunes, open, acidic temperate and boreal forests, high montane on acidic, sandy, or rocky soils  +
Arctostaphylos virgata +Maritime chaparral, open, closed-cone conifer forests  +
Arctostaphylos viridissima +Island chaparral, open forests  +
Arctostaphylos viscida subsp. mariposa +Chaparral, open forests  +
Arctostaphylos viscida subsp. pulchella +Chaparral, open forests  +
Arctostaphylos viscida subsp. viscida +Chaparral, open forests  +
Arctotheca calendula +Roadsides, old fields, other disturbed habitats  +
Arctotis fastuosa +Roadsides, urban waste places  +
Arctotis stoechadifolia +Roadsides, waste places, especially in sandy soils near coasts  +
Arctous alpina +Tundra, gravelly beach ridges, lichen heaths, open, boggy, coniferous woods, dry, wind-swept and snow-free fellfields in arctic and alpine tundra  +
Arctous rubra +Rocky and gravelly, arctic or alpine tundra, often in calcareous soils, coastal limestone heaths, swampy woods  +
Ardisia crenata +Acidic soil of suburban and urban woodlands and hardwood hammocks  +
Ardisia elliptica +Roadsides, scrub, near villages, edges of fields, along coasts  +
Ardisia escallonioides +Hammocks  +
Ardisia japonica +Acidic soil  +
Arenaria benthamii +Open woodlands, limestone slopes and outcrops  +
Arenaria humifusa +Moist, calcareous gravels and rock crevices  +
Arenaria lanuginosa var. lanuginosa +Forests, limestone outcrops, moist hummocks, dunes  +
Arenaria lanuginosa var. saxosa +Forests, stream banks  +
Arenaria livermorensis +Crevices of cliffs and bare walls  +
Arenaria longipedunculata +Gravelly, moist, montane areas, open alpine woods  +
Arenaria ludens +Igneous soil on cliffs and ledges  +
Arenaria paludicola +Boggy meadows, freshwater marshes  +
Arenaria pseudofrigida +Open, dry to slightly moist sand or gravel  +
Arenaria serpyllifolia var. serpyllifolia +Roadsides, open, sandy or rocky, disturbed sites  +
Arenaria serpyllifolia var. tenuior +Roadsides, open, sandy or rocky, disturbed sites  +
Arethusa bulbosa +Sphagnum bogs, coniferous swamps, calcareous treed to open fens, and moist, acid, sandy meadows  +
Argemone aenea +Dry plains and low hills, road and field margins  +
Argemone albiflora subsp. albiflora +Waste places, roadsides, fields, beaches, dunes, coastal plains  +
Argemone albiflora subsp. texana +Pastures and waste ground  +
Argemone arizonica +Precipitous slopes  +
Argemone aurantiaca +Fields, pastures, hills  +
Argemone chisosensis +Arid plains and mountains  +
Argemone corymbosa subsp. arenicola +Dry valleys and plains, especially around sand dune areas  +
Argemone corymbosa subsp. corymbosa +Dry flats and slopes, stabilized dunes, washes, sandy or granitic soil  +
Argemone gracilenta +Washes and outwash plains, deserts  +
Argemone hispida +Prairies, slopes, and eastern foothills of the Laramie and Rocky mountains  +
Argemone mexicana +Waste places, often a weed of roadsides, dooryards, fallow fields  +
Argemone munita subsp. argentea +Dry desert ranges  +
Argemone munita subsp. munita +Dry foothills and slopes  +
Argemone munita subsp. robusta +Dry, rocky soil, full sun  +
Argemone munita subsp. rotundata +Open slopes and foothills, full sun  +
Argemone ochroleuca +Disturbed soil, often a weed of fields, roadways, embankments, intermountain plains  +
Argemone pleiacantha subsp. ambigua +Dry slopes and embankments, foothills  +
Argemone pleiacantha subsp. pinnatisecta +Dry hills, pinyon-juniper zone  +
Argemone pleiacantha subsp. pleiacantha +Foothills and adjacent high plains  +
Argemone polyanthemos +Prairies, foothills and mesas  +
Argemone sanguinea +Coastal plains and westward  +
Argemone squarrosa subsp. glabrata +Arid slopes and valleys  +
Argemone squarrosa subsp. squarrosa +Prairies and foothills  +
Argyranthemum foeniculaceum +Disturbed sites  +
Argyrochosma dealbata +Calcareous cliffs and ledges  +
Argyrochosma fendleri +Rocky slopes and cliffs, usually on granitic or volcanic substrates  +
Argyrochosma incana +Sheltered cracks and ledges on canyon walls, restricted to rocks of volcanic origin in the flora  +
Argyrochosma jonesii +Calcareous cliffs and ledges  +
Argyrochosma limitanea subsp. limitanea +Rocky slopes and cliffs, usually on calcareous or volcanic substrates  +
Argyrochosma limitanea subsp. mexicana +Rocky slopes and cliffs, usually on calcareous or volcanic substrates  +
Argyrochosma microphylla +Rocky limestone hillsides and cliffs  +
Argythamnia adenophora +Desert scrub, rocky soils.  +
Argythamnia aphoroides +Bluestem-grama grasslands, oak woodlands, calcareous, often rocky, clay or loam soils.  +
Argythamnia argothamnoides +Open cactus hammocks, pinelands, mixed forests, rocky and sandy soils, limestone.  +
Argythamnia argyraea +Shortgrass grasslands or open shrublands on whitish, clay soils.  +
Argythamnia brandegeei var. intonsa +Desert scrub, rocky soils.  +
Argythamnia claryana +Desert scrub, rocky soils, basaltic hills.  +
Argythamnia cyanophylla +Scrub, pinyon-juniper woodlands, limestone-derived, rocky soils, damp zones near lakes.  +
Argythamnia humilis +Pine-oak forests, desert scrub, grasslands, limestone, sandstone, and clay soils.  +
Argythamnia lanceolata +Desert scrub, rocky soils.  +
Argythamnia mercurialina var. mercurialina +Flats, swamps, prairies, mesquite-yucca short grass communities, rocky hills, sandy soils, limestone.  +
Argythamnia mercurialina var. pilosissima +Oak woodlands and forests, grasslands, sandy soils.  +
Argythamnia serrata +Desert scrub, sandy, rocky, calcareous soils.  +
Argythamnia simulans +Grasslands, oak woodlands, loamy to clayey, calcareous, often rocky, soils.  +
Arida arizonica +Dry, open sandy flats, edges of playas, gravelly washes, riverbanks  +
Arida blepharophylla +Limestone areas, mountains  +
Arida carnosa +Alkaline flats, canyons, meadows  +
Arida mattturneri +Sulphur streams, tinajas  +
Arida parviflora +Saline flats, playas, swales, sandy areas, river margins  +
Arida riparia +Low valleys, saline soils on mudflats, edges of playas  +
Ariocarpus fissuratus var. fissuratus +Chihuahuan desert scrub, low, rocky hills of limestone chips  +
Arisaema dracontium +Mesic to wet deciduous woods, thickets, and bottoms  +
Arisaema triphyllum +Moist to dry deciduous woods and thickets, bottoms, swamps, and bogs.  +
Aristocapsa insignis +Sandy soil in grassland communities, and in pine-oak or juniper woodlands  +
Aristolochia californica +Along streams, in forest thickets, chaparral  +
Aristolochia clematitis +Waste places, roadsides, ballast  +
Aristolochia coryi +Rocky slopes, especially on limestone, occasionally river bottoms  +
Aristolochia erecta +Riverbanks, hillsides, chaparral  +
Aristolochia macrophylla +Forests, often on dissected uplands and rugged, rocky slopes, Cumberland and Blue Ridge mountains  +
Aristolochia maxima +Hammocks  +
Aristolochia pentandra +Wet Caribbean-type lowlands  +
Aristolochia reticulata +Moist, sandy soils  +
Aristolochia serpentaria +Mesic forests  +
Aristolochia tomentosa +Alluvial soils along rivers and streams  +
Aristolochia watsonii +Rocky slopes  +
Aristolochia wrightii +Rocky slopes  +
Arivela viscosa +Disturbed roadsides, vacant lots, citrus groves, railroads, ballasts  +
Armeria maritima subsp. californica +Maritime rocks, cliffs, sandy bluffs, sandy dunes  +
Armeria maritima subsp. interior +Sand dunes, gravel pavements  +
Armeria maritima subsp. maritima +Maritime rocks, cliffs  +
Armeria maritima subsp. sibirica +Gravelly tundras, flood plains, lakes and seashores, alpine meadows  +
Armoracia rusticana +Fields, moist stream banks, roadsides, ditches, disturbed sites, open woods, along railroads, shallow ponds, marshes, waste places  +
Arnica acaulis +Sandy pine woods and clearings, often in damp soils, chiefly on Coastal Plain  +
Arnica angustifolia subsp. angustifolia +Alpine slopes and ridges to Arctic tundra  +
Arnica angustifolia subsp. tomentosa +Alpine slopes and subalpine meadows  +
Arnica cernua +Serpentine soils, conifer forests  +
Arnica chamissonis +Moist meadows and conifer forests, stream banks, late snow-melt areas, often montane to subalpine  +
Arnica cordifolia +Conifer forests to subalpine meadows  +
Arnica dealbata +Open forests, meadows, slopes  +
Arnica discoidea +Chaparral, oak and pine forests  +
Arnica fulgens +Prairies and grasslands to montane conifer forests  +
Arnica gracilis +Dry, exposed, rocky, alpine slopes, sometimes subalpine meadows  +
Arnica griscomii subsp. frigida +Alpine meadows, tundras, and calcareous rocky outcrops  +
Arnica griscomii subsp. griscomii +Sea-cliffs, limestone barrens, hornblende schists and dry schistose talus in alpine areas  +
Arnica lanceolata subsp. lanceolata +Moist areas, stream banks, gravel bars, to subalpine meadows  +
Arnica lanceolata subsp. prima +Moist areas, along stream banks, snow-melt areas, montane to alpine meadows  +
Arnica latifolia +Relatively moist, montane conifer forests to subalpine meadows  +
Arnica lessingii +Coastal tundra to alpine slopes  +
Arnica lonchophylla +Dry to mesic, open montane slopes, open woodlands, stream gravels, shorelines, calcareous rocky outcrops, to lowland Arctic tundra  +
Arnica longifolia +Montane coniferous forests to alpine, usually moist areas, stream banks or late snow-melt areas  +
Arnica louiseana +Exposed tundra slopes and calcareous rock slides  +
Arnica mollis +Moist meadows and conifer forests, stream banks, late snow-melt areas, montane to subalpine  +
Arnica nevadensis +Coniferous forests, meadows, rocky slopes  +
Arnica ovata +Moist meadows and conifer forests, stream banks, late snow-melt areas, montane to subalpine  +
Arnica parryi +Open conifer forests to alpine meadows  +
Arnica rydbergii +Dry to mesic, exposed, rocky alpine slopes and ridges or alpine meadows  +
Arnica sororia +Prairies and grasslands to montane conifer forests  +
Arnica spathulata +Usually serpentine soils, open, dry oak–conifer forests, disturbed areas  +
Arnica unalaschcensis +Coastal tundra to alpine slopes  +
Arnica venosa +Open, often disturbed, oak-pine forests  +
Arnica viscosa +Open, rocky subalpine to alpine  +
Arnoglossum album +Poorly drained, acidic loamy sands, savannas, open pinewoods  +
Arnoglossum atriplicifolium +Edges of woods, pastures, roadsides  +
Arnoglossum diversifolium +Wet or mucky soils, along streams, swamps, woodlands  +
Arnoglossum floridanum +Dry sand ridges, pine-oak woodlands  +
Arnoglossum ovatum +Wet, sandy woods, lowlands, savannas, roadsides  +
Arnoglossum plantagineum +Wet prairies and pastures, usually in boggy areas in north  +
Arnoglossum reniforme +Open woods  +
Arnoglossum sulcatum +Shaded, wet areas of hillside seepages, thickets, and swamps  +
Arnoseris minima +Disturbed sites, sandy soils  +
Aronia arbutifolia +Swamps, wet thickets, peatland pocosins, bogs, fens, wet pine flatwoods, margins of freshwater wetlands, beaver ponds, mixed loblolly pine, Magnolia virginiana-Rhus vernix-swamps, black gum swamps  +
Aronia melanocarpa +Swamps, bogs, wet thickets, margins of ponds and lakes, beaver ponds, woods, moist high-elevation forests, rock outcrops  +
Arrhenopterum heterostichum +Mineral or humid soil, slopes of ravines, bark at tree bases  +
Artemisia abrotanum +Waste places  +
Artemisia absinthium +Widely cultivated, persisting from plantings, disturbed areas  +
Artemisia alaskana +Well-drained soils, flood plains, gravel stream banks, roadsides, dry, rocky slopes, forest openings, alpine and arctic tundras  +
Artemisia aleutica +Open areas, fellfield tundra  +
Artemisia annua +Moist waste areas, sandy soils  +
Artemisia arbuscula subsp. arbuscula +Rocky sedimentary soils, high valleys, mountain slopes  +
Artemisia arbuscula subsp. longiloba +Clay soils of alkaline basins and valleys, occasionally on outwash plains of mountains  +
Artemisia arbuscula subsp. thermopola +Rocky soils of igneous origin  +
Artemisia biennis +Disturbed habitats, margins of vernal pools, desert flats, usually clay or silty soils  +
Artemisia bigelovii +Deserts, sandy or alkaline soils, rock outcrops  +
Artemisia borealis subsp. borealis +Open meadows, usually on well-drained soils  +
Artemisia borealis subsp. richardsoniana +River terraces, tundra  +
Artemisia californica +Coastal scrub, dry foothills  +
Artemisia campestris subsp. canadensis +Open meadows  +
Artemisia campestris subsp. caudata +Open meadows, usually moist soils, sometimes sandy or rocky habitats  +
Artemisia campestris subsp. pacifica +Sandy soils, arid regions  +
Artemisia cana subsp. bolanderi +Gravel soils, mountain meadows, stream banks  +
Artemisia cana subsp. cana +Sandy loam soils, often along streams  +
Artemisia cana subsp. viscidula +Wet mountain meadows, stream banks, rocky areas with late-lying snows  +
Artemisia carruthii +Open sites, usually sandy soils, wooded areas, grasslands, railroads  +
Artemisia douglasiana +Meadows, shaded sites, along drainages  +
Artemisia dracunculus +Open meadows and fields, desert scrub, moist drainages, roadsides  +
Artemisia filifolia +Open prairies, dunes, sandy soils  +
Artemisia franserioides +Open coniferous forests, mid to upper montane  +
Artemisia frigida +Fields, meadows, dry grasslands, steppes, usually stony, well-drained soils  +
Artemisia furcata +Talus slopes or tundra  +
Artemisia globularia subsp. globularia +Arctic and alpine tundra, interior mountains  +
Artemisia globularia subsp. lutea +Rocky ridges and slopes  +
Artemisia glomerata +Arctic and alpine tundra and sandy slopes  +
Artemisia laciniata subsp. laciniata +Dry, gravelly stream banks, grassy flats, forested areas, dry hillsides  +
Artemisia laciniata subsp. parryi +Subalpine and alpine meadows, rocky soils  +
Artemisia longifolia +Alkaline flats, grasslands, barren areas, high plains  +
Artemisia ludoviciana subsp. albula +Desert drainages, sandy soils  +
Artemisia ludoviciana subsp. candicans +Mountains, usually in loamy soils  +
Artemisia ludoviciana subsp. incompta +Open meadows, mountain slopes  +
Artemisia ludoviciana subsp. ludoviciana +Disturbed roadsides, open meadows, rocky slopes  +
Artemisia ludoviciana subsp. mexicana +Mountain slopes, rocky soils  +
Artemisia ludoviciana subsp. redolens +Rocky loam soils  +
Artemisia michauxiana +Talus slopes, alpine and subalpine drainages  +
Artemisia nesiotica +Rocky slopes, often fog-shrouded hillsides  +
Artemisia norvegica subsp. saxatilis +Coastal, arctic, subalpine to alpine habitats, boreal forests, moist soils  +
Artemisia nova +Shallow soils, desert valleys, exposed mountain slopes  +
Artemisia packardiae +Coarse taluses, alkaline soils, erosion gullies  +
Artemisia palmeri +Ravines, coastal areas, sandy soils  +
Artemisia papposa +Rocky swales, dry meadows, alkaline mud flats  +
Artemisia pattersonii +Alpine meadows  +
Artemisia pedatifida +High plains, grasslands  +
Artemisia pontica +Disturbed areas, valleys, shaded thickets  +
Artemisia porteri +Barren clay and gravelly soils  +
Artemisia pycnocephala +Rocky or sandy soils of coastal beaches  +
Artemisia pygmaea +Fine-textured soils of gypsum or shale  +
Artemisia rigida +Dry rocky scablands, volcanic plains  +
Artemisia rothrockii +Clay soils of mountain meadows  +
Artemisia rupestris +Steppes, alkaline meadows, stony slopes  +
Artemisia scopulorum +Alpine meadows, protected areas, bases of rocks  +
Artemisia senjavinensis +Open calcareous gravelly slopes in tundra or heath, sandy slopes above high tide  +
Artemisia serrata +Grasslands and barren areas on high plains  +
Artemisia spiciformis +Moist open slopes, rocky meadows, streamsides, woodlands, late-lying snowfields  +
Artemisia stelleriana +Sandy soils, coastal strand  +
Artemisia suksdorfii +Coastal habitats, often along roads or drainages  +
Artemisia tilesii +Arctic and alpine tundra, sandy, rocky slopes near shorelines  +
Artemisia tridentata subsp. parishii +Loose sandy soils of valleys and foothills  +
Artemisia tridentata subsp. tridentata +Deep, well-drained (usually sandy) soils in valley bottoms, lower montane slopes, along drainages  +
Artemisia tridentata subsp. vaseyana +Montane meadows, usually in rocky soils, sometimes in forested areas  +
Artemisia tridentata subsp. wyomingensis +Rocky or fine-grained soils, cold-desert basins to high plateaus, foothills  +
Artemisia tripartita subsp. rupicola +Shallow rocky soils, grasslands  +
Artemisia tripartita subsp. tripartita +Deep loam soils, usually igneous in origin  +
Artemisia vulgaris +Sandy or loamy soils, forested areas, coastal strands, roadsides  +
Arthrocnemum subterminale +Salt marshes, depressions in alkali sage scrub  +
Aruncus dioicus var. acuminatus +Moist to wet ravines, rocky ledges, avalanche tracks, stream banks, forest edges and openings  +
Aruncus dioicus var. dioicus +Rich woods, stream banks, north-facing roadsides, seeps, ditches  +
Aruncus dioicus var. pubescens +Rich woods, limestone bluffs  +
Aruncus dioicus var. vulgaris +Rich woods  +
Asanthus squamulosus +Flats, gravel banks, arroyos, pine-oak woodlands  +
Asarum canadense +Understory of deciduous (rarely coniferous) forests  +
Asarum caudatum +Understory of conifer forests, usually in mesic or wet places  +
Asarum hartwegii +Rocky slopes in dry conifer or oak forests  +
Asarum lemmonii +Wet places, usually near creeks, in understory of conifer forests  +
Asarum marmoratum +Understory of dry or mesic forests, or exposed rocky slopes or roadcuts  +
Asarum wagneri +Understory of Abies forests and open boulder fields in Tsuga forests near timberline  +
Aschisma kansanum +Usually under translucent rocks in exposed situations  +
Asimina incana +Sands or sandy loams, upland oak-pineland, pastures, disturbed sandy sites, mostly in longleaf pine-turkey oak systems  +
Asimina longifolia var. longifolia +Sands and sandy peats or loams of yellow sandhills, sandy fields and pastures, open longleaf pine-turkey oak woods and savannas  +
Asimina longifolia var. spatulata +Sands or sandy peats or loams of rises in pine savanna, pine flatwoods, or sandhills, sandy fields, and pastures  +
Asimina obovata +White and yellow sand ridges, mostly in oak-pine woods, scrub, coastal dunes, and hammock edges  +
Asimina parviflora +Sands, sandy loams, or sandy alluvium of rich woods, alluvial terraces, and upland dry woods  +
Asimina pygmaea +Sandy peat of pine-palmetto flats, savannas, low sandy fields, and low sand ridges  +
Asimina reticulata +Moist sands and sandy peat of pine-palmetto flats, savannas, low fields  +
Asimina tetramera +Sands of ancient coastal dunes and adjacent open-wooded hammocks, flatwoods  +
Asimina triloba +Mesic woods, often alluvial sites, fencerows  +
Asparagus aethiopicus +Waste places, abandoned gardens  +
Asparagus asparagoides +Waste places, open forests, roadsides  +
Asparagus officinalis +Fields, fencerows, roadsides, disturbed areas  +
Asparagus setaceus +Waste places, abandoned gardens  +
Asphodelus fistulosus +Roadsides, fields, waste places  +
Aspicarpa hirtella +Dry rocky slopes among boulders, grassy slopes with oaks, pines, junipers.  +
Aspicarpa hyssopifolia +Brushy, dry, calcareous slopes.  +
Aspidotis californica +Rocky outcrops and crevices (not serpentine), moist to dry, shaded slopes and cliffs  +
Aspidotis densa +Slopes, crevices, rocky outcrops, often on serpentine, sometimes in chaparral  +
Asplenium abscissum +Shaded limestone boulders, cliff ledges, grottoes, sinkholes  +
Asplenium adiantum-nigrum +Cliffs  +
Asplenium adulterinum +Crevices in limestone  +
Asplenium auritum +Mainly epiphytic on old sloping tree trunks in shady forests  +
Asplenium bradleyi +Acidic rocks, usually on steep ledges  +
Asplenium cristatum +Low limestone boulders and ledges in deep moist woods  +
Asplenium dalhousiae +Moist, rocky ravines, terrestrial among and at bases of rocks  +
Asplenium ebenoides +Conglomerate boulders  +
Asplenium exiguum +Cliffs  +
Asplenium heterochroum +Sinkholes, limestone rocks in shady hammocks, masonry  +
Asplenium monanthes +Rock  +
Asplenium montanum +Crevices in sandstone or other acidic rocks  +
Asplenium palmeri +Shaded rocky slopes, wet ledges, often in protected places  +
Asplenium pinnatifidum +Cliffs, ledges, and boulders of sandstone and other acidic rocks  +
Asplenium platyneuron +Forest floor or on rocks, often invading masonry and disturbed soils  +
Asplenium plenum +Limestone rocks in shaded forests  +
Asplenium pumilum +Shaded limestone boulders  +
Asplenium resiliens +Cliffs, sinkholes, on limestone or other basic rocks  +
Asplenium rhizophyllum +Shaded, usually moss-covered boulders and ledges, usually on limestone or other basic rocks, but occasionally on sandstone or other acidic rocks, rarely on fallen tree trunks  +
Asplenium ruta-muraria +Limestone (or calcareous shale) cliffs and boulders, rarely invading masonry  +
Asplenium scolopendrium var. americanum +On calcareous rocks in sinkholes, at cave entrances, and on cool, moist talus, always in deep shade  +
Asplenium septentrionale +Cliffs of various substrates  +
Asplenium serratum +Rotten logs and stumps  +
Asplenium trichomanes subsp. quadrivalens +Calcareous rocks such as limestone and dolomite  +
Asplenium trichomanes subsp. trichomanes +Acidic rocks such as sandstone, basalt, and granite, very rarely on calcareous rocks  +
Asplenium trichomanes-dentatum +Shady hammocks, on walls of limesinks, moist limestone rocks, rocky banks of streams  +
Asplenium trichomanes-ramosum +Limestone and other basic rocks  +
Asplenium verecundum +Limestone outcrops in grottoes, on cliffs, and on boulders in shaded woods  +
Asplenium vespertinum +Moist, shaded canyon walls and at base of overhanging rocks  +
Asplenium ×biscayneanum +Hammocks, on limestone rock faces  +
Asplenium ×curtissii +Shaded damp limestone rocks  +
Asplenium ×heteroresiliens +Limestone rocks  +
Aster alpinus subsp. vierhapperi +Open to semishaded, mesic to dry, rocky, gravelly or silty, often calcareous areas, alpine tundra, montane to alpine meadows, cold prairies, Artemisia steppes, gravelly or eroding stream banks and flats, edges of open riparian boreal forests, bluffs, talus and cliffs, sandy ridges in muskeg  +
Aster tataricus +Fields, open roadsides  +
Astilbe biternata +Rich woods and shaded north-facing road banks, ditches and seeps  +
Astraea lobata +Open areas, disturbed habitats.  +
Astranthium ciliatum +Open sandy sites, less commonly in loam or clay, oak and oak-hickory woodlands, roadsides, pastures, grassland, also occasionally (Ark., Okla.) on rocky ridges, limestone outcrops, gravelly stream bottoms  +
Astranthium integrifolium +Rocky (limestone) banks and ridges, alluvial fields, stream banks and terraces, open juniper woods, glades, roadsides  +
Astranthium robustum +Disturbed sites in sandy or rocky soil, mesas, canyons, pine flats, roadsides, ditches  +
Astrolepis cochisensis subsp. arizonica +Rocky slopes and cliffs, favoring granite, quartzite, and other noncalcareous substrates, occasionally found on limestone  +
Astrolepis cochisensis subsp. chihuahuensis +Rocky calcareous slopes and cliffs, mostly on limestone  +
Astrolepis cochisensis subsp. cochisensis +Rocky slopes and cliffs, favoring limestone and other calcareous substrates  +
Astrolepis integerrima +Rocky hillsides and cliffs, usually on limestone or other calcareous substrates  +
Astrolepis sinuata subsp. mexicana +Rocky slopes and cliffs, occurring on calcareous and noncalcareous substrates  +
Astrolepis sinuata subsp. sinuata +Rocky slopes and cliffs, occurring on calcareous and noncalcareous substrates  +
Astrolepis windhamii +Rocky hillsides and cliffs, occurring on calcareous and noncalcareous substrates  +
Astrophytum asterias +Grasslands, shrublands, Tamaulipan thorn scrub, gravelly slopes and deep soil of flats  +
Atamisquea emarginata +Desert scrub, arroyos or flats  +
Athyrium distentifolium var. americanum +Wet talus slopes, rocky hillsides, alpine meadows  +
Athyrium filix-femina var. angustum +Moist woods, swamps, thickets  +
Athyrium filix-femina var. asplenioides +Moist woods, thickets, swamps  +
Athyrium filix-femina var. californicum +Moist woods, meadows, streambanks  +
Athyrium filix-femina var. cyclosorum +Moist woods, swamps, streambanks  +
Athysanus pusillus +Open grassy slopes, grassy glades in woodlands, chaparral, sandy and gravelly flats, flood plains, rock outcrops, cliffs and ledges, on limestone, serpentine, sandstone, granitic and basaltic substrates  +
Athysanus unilateralis +Open grassy slopes and flats, friable clay, flood plains, adobe and heavy gumbo clay, gypsum clay slopes  +
Atrichoseris platyphylla +Dry desert slopes, valleys, and washes  +
Atrichum altecristatum +Soil banks along roads, trails, often on hummocks in clearings in woodlands, open or semishaded conditions  +
Atrichum angustatum +Exposed soil banks along roads and trails in woods  +
Atrichum crispulum +Soil, humus, mostly shaded habitats, often wet banks along streams or sometimes at margins of fens and swamps  +
Atrichum crispum +Sandy soil along streams, roadside ditches in shaded habitats, sometimes at margins of swamps and marshes, rarely on rotting logs in woods  +
Atrichum cylindricum +Moist soil, ravines, ditches, stream banks in mixed forest, low wet woods and bottomland (swamp forest)  +
Atrichum flavisetum +Banks or stumps in woods, roots of fallen trees, ravines in crevices of rock outcrops  +
Atrichum selwynii +Soil, open and shaded habitats, bare roadside banks, overturned tree roots  +
Atrichum tenellum +Clay or sandy soil, especially in exposed habitats, beside streams, in roadside ditches, along trails and clearings in woodlands  +
Atrichum undulatum +Soil, dry weedy habitats, especially roadside ditches  +
Atriplex acanthocarpa var. acanthocarpa +Alkaline soils, used for windbreaks, roadside cover and ornamentals, mainly occurring along the drainages of the Gila and Rio Grande rivers  +
Atriplex acanthocarpa var. coahuilensis +Saline, often fine-textured soils  +
Atriplex amnicola +Sea beaches  +
Atriplex argentea var. argentea +Dry or saline substrates  +
Atriplex argentea var. hillmanii +Dry or moist saline, silt or clay substrates mainly in valley bottoms  +
Atriplex argentea var. longitrichoma +Saline valley bottoms, with shrubby saltbush, creosote bush, mesquite, and annual weedy grasses and forbs  +
Atriplex argentea var. mohavensis +Dry or saline substrates  +
Atriplex argentea var. rydbergii +Saline, fine-textured substrates derived mainly from Mancos Shale and Morrison formations and clay or silty alluvium, growing in salt desert shrub and floodplain communities  +
Atriplex californica +Sea bluffs, sandy coasts, crevices in sea cliffs, coastal strands, edges of coastal salt marsh, coastal sage scrub  +
Atriplex canescens var. canescens +Sandy or gravelly, commonly non-saline but in other situations obviously saline, sites in Joshua tree, blackbrush, greasewood, salt desert shrub, sagebrush, mountain brush, and pinyon-juniper communities  +
Atriplex canescens var. gigantea +Active sand dunes  +
Atriplex canescens var. laciniata +Saline flats, bajadas, alluvial fans  +
Atriplex canescens var. macilenta +Saline desert flats, alluvial fans  +
Atriplex confertifolia +Gravelly to fine-textured soils in greasewood, mat-atriplex, other salt desert shrub, sagebrush, pinyon-juniper, and ponderosa pine communities  +
Atriplex cordulata var. cordulata +Hard trampled, somewhat saline or alkaline soils  +
Atriplex cordulata var. erecticaulis +Roadsides, fields, in alkaline grasslands  +
Atriplex coronata var. coronata +Alkaline sink scrub, growing with Atriplex polycarpa and other salt desert shrubs and forbs  +
Atriplex coronata var. notatior +Alkaline flats, dry lake beds, with Suaeda, Atriplex spp., and other salt-tolerant species  +
Atriplex coronata var. vallicola +Dried rain pools and flats, alkaline soils  +
Atriplex corrugata +Saline, usually fine-textured substrates derived from Mancos Shale, Tropic Shale, Morrison, Duchesne River, and other similar formations in mat-atriplex and Castle Valley saltbush communities  +
Atriplex coulteri +Somewhat alkaline or clay low places, valley grasslands, coastal sage scrub, coastal slopes  +
Atriplex covillei +Mixed saltbush-greasewood, rabbitbrush, warm desert shrub, and salt grass communities in saline substrates  +
Atriplex dioica +Sea beaches, other saline habitats  +
Atriplex elegans var. elegans +Saline creosote bush scrub, deserts  +
Atriplex elegans var. fasciculata +Alkaline flats, valley grasslands, deserts  +
Atriplex fruticulosa +Clay or alkaline soils, open site, shrublands  +
Atriplex gardneri var. aptera +Saline, often moist, fine-textured substrates  +
Atriplex gardneri var. bonnevillensis +Greasewood and saltbush communities in valley bottoms and playas  +
Atriplex gardneri var. cuneata +Saline, fine-textured substrates on Mancos Shale, and other formations of similar texture and salinity, in greasewood and mat-atriplex communities  +
Atriplex gardneri var. falcata +Sagebrush, shadscale, and greasewood communities in fine-textured saline substrates  +
Atriplex gardneri var. gardneri +Greasewood and sagebrush-saltbush communities, mainly on fine-textured saline substrates  +
Atriplex gardneri var. utahensis +Greasewood, shadscale,alkali sacaton, kochia, saltbush, saltgrass, and sedge-rush communities, on fine-textured saline substrates  +
Atriplex gardneri var. welshii +Mat-atriplex and Castle Valley saltbush communities on Mancos Shale Formation  +
Atriplex garrettii var. garrettii +Shadscale, rabbitbrush, ephedra, eriogonum, blackbrush, and mixed shrub-grass communities on fine-textured substrates, talus slopes of canyons of the San Juan and Colorado Rivers  +
Atriplex garrettii var. navajoensis +Sandstone or limestone rimrock  +
Atriplex glabriuscula var. acadiensis +Salt marshes, with Spartina patens  +
Atriplex glabriuscula var. franktonii +Sandy beaches, often covered with wrack of fucoids and Chondrus  +
Atriplex glabriuscula var. glabriuscula +Sandy sea beaches, exposed cobble, ledges, boulders  +
Atriplex gmelinii var. alaskensis +Coastal salt marsh, with Zostera, Elymus, and other strand and beach plants, from below high-tide level  +
Atriplex gmelinii var. gmelinii +Seashores, strands, salt marshes  +
Atriplex graciliflora +Saltbush, mat-atriplex, seepweed, greasewood, rabbitbrush, and tamarix communities on saline, often salt encrusted and semibarren substrates derived from Mancos Shale, Tropic Shale, Entrada, and other fine-textured formations  +
Atriplex heterosperma +Riparian and palustrine (less commonly ruderal) habitats  +
Atriplex holocarpa +Cultivated or weedy  +
Atriplex hortensis +Roadsides, canal and stream banks, lake shores, disturbed sites and gardens  +
Atriplex hymenelytra +Warm desert shrub, on dry saline alluvial fans and hills  +
Atriplex joaquiniana +Alkali sink scrub or alkaline grasslands  +
Atriplex klebergorum +In silty or clay loam soils  +
Atriplex laciniata +Sand, cobble on more or less protected beaches, on Zostera and Fucus wrack  +
Atriplex lentiformis +Saline to essentially non-saline drainages, stream and canal banks, roadsides, warm desert shrub, saltbush, and riparian communities  +
Atriplex leucophylla +Sea beaches, along coasts, at higher elevation inland  +
Atriplex lindleyi +Sparingly escaped from cultivation  +
Atriplex linearis +Saline deserts, with shadscale, Canotia, Yucca, Opuntia, Rhus, and Eriogonum  +
Atriplex littoralis +Sea beaches and other saline habitats, old ports and ballast dumps  +
Atriplex matamorensis +Saline soils, coastal areas, often along roadsides, other disturbed areas  +
Atriplex mucronata +Sandy seashores, salt marshes  +
Atriplex nudicaulis +Coastal sites  +
Atriplex nummularia +Sandy coastal bluffs, disturbed sites such as roadsides  +
Atriplex oblongifolia +Ruderal  +
Atriplex obovata +Fine-textured substrates, with salt desert shrub and lower pinyon-juniper communities  +
Atriplex pacifica +Mainly on sea bluffs  +
Atriplex parishii var. depressa +Alkaline grasslands, often on clay soils  +
Atriplex parishii var. minuscula +Sandy saline substrates  +
Atriplex parishii var. parishii +Saline substrates  +
Atriplex parishii var. persistens +Saline or alkaline depressions or vernal pools  +
Atriplex parishii var. subtilis +Saline depressions, often within or later growing in depressions of vernal pools  +
Atriplex parryi +Saline, fine-textured soils  +
Atriplex patula +Widespread ruderal weed of nonsaline substrates such as fields, gardens, and roadsides  +
Atriplex pentandra +Sandy seashores, coastal salt marshes  +
Atriplex phyllostegia +Valley bottoms, silty or clay, less commonly, sandy alluvium with greasewood  +
Atriplex pleiantha +Salt-desert shrub community  +
Atriplex polycarpa +Warm desert shrub communities (creosote bush, ambrosia, shadscale, mesquite, saltgrass, etc.), mainly in fine-textured saline substrates  +
Atriplex powellii var. minuticarpa +Tununk and Blue Gate members Mancos Shale Formation and on Morrison Formation, and likely on other fine-textured saline substrates, with mat-atriplex, greasewood, rabbitbrush, and shadscale communities  +
Atriplex powellii var. powellii +Saline, usually fine-textured clay or silty substrates, in greasewood, rabbitbrush, shadscale, seepweed, mat-atriplex, juniper-pinyon, and blackbrush communities  +
Atriplex prostrata +Sea beaches, salt marshes or other saline habitats  +
Atriplex pusilla +Saline substrates in valley bottoms, playas, and along drainages with greasewood, rabbitbrush, shadscale, and sagebrush  +
Atriplex rosea +Disturbed sites, often in riparian habitats or in barnyards or on animal bed grounds, along roadsides and irrigation canals, with juniper, sagebrush, rabbitbrush, pinyon-juniper, Salsola, Chrysothamnus, Atriplex spp., and other weedy species  +
Atriplex saccaria var. asterocarpa +Fine-textured, saline (frequently semibarren) substrates of the Chinle and Entrada formations, with Atriplex confertifolia, Phacelia crenulata, and Eriogonum inflatum  +
Atriplex saccaria var. cornuta +Salt desert shrub communities, on fine-textured saline substrates of Morrison and Mancos Shale formations  +
Atriplex saccaria var. saccaria +Mat-atriplex, shadscale, greasewood, and pinyon-juniper communities, on fine-textured saline substrates (often semibarren) of the Bridger, Duchesne River, Mancos Shale, Dakota, Morrison, Entrada, and Chinle formations, and on fine-textured alluvium  +
Atriplex semibaccata +Saline waste places, along roads and sidewalks, in marshes, in various plant communities  +
Atriplex serenana var. davidsonii +Bluffs, alkaline sinks and drainages  +
Atriplex serenana var. serenana +Alkaline valleys, marshy areas, valley grasslands, coastal sage scrub, sometimes ruderal weed  +
Atriplex spinifera +Xeric saline substrates, with mixed salt desert shrubs  +
Atriplex suberecta +Disturbed places, with other ruderal weeds  +
Atriplex suckleyi +Alkaline or saline, typically fine-textured substrates, often on shale or clay barrens, sometimes with other Atriplex spp., sagebrush, and grasses  +
Atriplex tatarica +Atlantic and Gulf coasts, ballast and waste grounds  +
Atriplex torreyi var. griffithsii +Saline flats  +
Atriplex torreyi var. torreyi +Mesquite, creosote bush, greasewood, rabbitbrush, shadscale, saltgrass, saltbush, and blackbrush communities, mainly in saline substrates  +
Atriplex truncata +Saline saltgrass-greasewood-rabbitbrush communities, and other pans or palustrine or lacustrine habitats  +
Atriplex tularensis +Alkaline plains, edges of alkali sink  +
Atriplex watsonii +Coastal and insular bluffs, beaches, strands, salt marshes, sage scrub, with saltgrass and other salt-tolerant species  +
Atriplex wolfii var. tenuissima +Plants of saline bottoms, often in margins of marshy areas with salt grass, greasewood, and seepweed  +
Atriplex wolfii var. wolfii +Saline areas growing with shadscale, seepweed, Russian thistle, fine-textured substrates  +
Atriplex wrightii +In alkaline or saline substrates, often along roadsides, in old fields and vacant lots  +
Aubrieta deltoidea +Rock crevices  +
Aucuba japonica +Thickets, brushy hillsides, near botanical gardens, suburban woodlands.  +
Aulacomnium acuminatum +Arctic tundra meadows, hummocks, polygon edges, organic or mineral soil, calcareous sites, deep canyons  +
Aulacomnium androgynum +Organic soil, rotting logs, mineral soil over rock  +
Aulacomnium palustre +Wet habitats, fens, marshes, swamps, peat, organic soil, moist to wet mineral soil, rock  +
Aulacomnium turgidum +Arctic and alpine tundra meadows, heaths, fellfields, mineral soil, rock, near tree line under spruce, cirque headwalls, deep shaded canyons  +
Aureolaria flava +Oak or oak-pine woods, roadsides.  +
Aureolaria grandiflora +Maple, pine, and oak woodlands, roadsides.  +
Aureolaria levigata +Rocky wooded slopes, mixed hardwoods.  +
Aureolaria patula +Limestone substrates, edges of lakes or streams.  +
Aureolaria pectinata +Sandy soils, oak-pine scrubs.  +
Aureolaria pedicularia +Roadsides, oak woods, pine barrens, clearings, dry, sandy soils.  +
Aureolaria virginica +Oak and pine woods and slopes.  +
Aurinia petraea +Cliffs, gorges, rocky slopes  +
Aurinia saxatilis +Ledges, cliffs, rocky slopes  +
Axyris amaranthoides +Waste places  +
Ayenia compacta +Rocky slopes, gravelly or sandy washes, dry canyons  +
Ayenia euphrasiifolia +Marl over limestone, pinelands, sandy scrub, rocky flats, waste places  +
Ayenia filiformis +On limestone and granite soil, steep rocky slopes, canyons, sandy washes  +
Ayenia jaliscana +Rocky slopes, canyon bottoms, desert grasslands  +
Ayenia limitaris +Subtropical thorn woodlands or tall shrublands, calcareous or fine sandy loam to heavy clay alluvial soil  +
Ayenia microphylla +Dry limestone, igneous rocky slopes  +
Ayenia pilosa +Edges of thickets  +
Azolla caroliniana +Stagnant or slow-moving water in ponds, lakes, marshess, swamps, and streams.  +
Azolla filiculoides +Stagnant and slow-moving waters.  +
Azolla mexicana +Stagnant or slow-moving waters.  +
Baccharis angustifolia +Coastal salt marshes, hammocks, dune hollows, stream banks  +
Baccharis bigelovii +Dry rocky ground in coniferous forests  +
Baccharis brachyphylla +Canyons, dry washes, sandy deserts, mesas  +
Baccharis dioica +Hammocks and dune hollows, mangroves  +
Baccharis douglasii +Moist salt marshes, coastal strands, stream edges, hillsides, railroads  +
Baccharis glomeruliflora +Hammocks, moist woods, pine woods, swamps, swales, stream banks, ditches of inner dunes  +
Baccharis halimifolia +Open sandy places, wet fields, marshes, beaches, disturbed sites, roadsides, old fields  +
Baccharis havardii +Dry rocky hillsides, open ground, calcareous gravels  +
Baccharis malibuensis +Grassy openings, chaparral  +
Baccharis neglecta +Disturbed habitats, old fields, pastures, roadsides, streambeds  +
Baccharis pilularis subsp. consanguinea +Oak woodlands, coniferous forest openings, roadsides, coastal bluffs  +
Baccharis pilularis subsp. pilularis +Exposed, sandy coastal bluffs and beaches  +
Baccharis plummerae subsp. glabrata +Rocky slopes near beaches, sea bluffs, serpentine rock outcrops, chaparral, brushy canyons, woodlands  +
Baccharis plummerae subsp. plummerae +Rocky slopes near beach, sea bluffs, brushy canyons, oak woodlands  +
Baccharis pteronioides +Dry canyons, roadsides, open oak woodlands, grasslands  +
Baccharis salicifolia +Stream banks, dry washes, sandy flood plains, riparian woodlands, disturbed sites, ditches  +
Baccharis salicina +Stream banks, alkaline meadows, roadsides  +
Baccharis sarothroides +Gravelly and sandy washes, roadsides, railroads, mesquite flats, chaparral  +
Baccharis sergiloides +Gravelly or sandy streambeds, dry washes, grasslands  +
Baccharis texana +Dry prairies, hillsides, mesas, brushy flats  +
Baccharis thesioides +Mountains and canyons, oak-pine forests  +
Baccharis vanessae +Chaparral, Torrey-pine forests  +
Baccharis wrightii +Dry sandy plains  +
Bacopa caroliniana +Marshes, swamps, margins of streams, pastures.  +
Bacopa egensis +Shallow, quiescent water, lakes.  +
Bacopa eisenii +Marshes, ponds, pools, wet soil, wet ditches, rice fields.  +
Bacopa innominata +Marshy areas, alluvial deposits along streams, wet ditches, muddy shores and banks.  +
Bacopa monnieri +Wetlands, wet sands, mud flats, riparian areas.  +
Bacopa repens +Muddy sites, pools, rice fields.  +
Bacopa rotundifolia +In water or on mud in lakes, ponds, pools, in and around marshes and ditches, ephemeral pools on rock outcrops.  +
Bahia absinthifolia +Sandy soils with mesquite or desert scrubs, calcareous places  +
Bahia bigelovii +Sandy soils  +
Bahia biternata +Granite outcrops  +
Bahia pedata +Sandy soils, limestone, openings in grasslands and pinyon-juniper woodlands  +
Bahiopsis laciniata +Xeric scrub  +
Bahiopsis parishii +Xeric scrub  +
Bahiopsis reticulata +Xeric scrub, desert grottoes and canyons  +
Baileya multiradiata +Stony slopes, mesas, and sandy plains  +
Baileya pauciradiata +Sandy soils, deserts  +
Baileya pleniradiata +Sandy plains and mesas  +
Balduina angustifolia +Dry sandy soils, especially in pinelands  +
Balduina atropurpurea +Pitcher plant bogs, wet pinelands and savannas  +
Balduina uniflora +Moist to dry pinelands and savannas  +
Balsamorhiza careyana +Dry scablands, semi-desert soils, openings in pine forests  +
Balsamorhiza deltoidea +Open hillsides, openings in chaparral or forests  +
Balsamorhiza hispidula +Basalt scablands and desert-steppe areas, juniper and sagebrush scrublands  +
Balsamorhiza hookeri +Rocky outcrops, dry meadows, sagebrush scrublands, basalt scablands (north), dry, open forests (south)  +
Balsamorhiza incana +Grassy meadows, dry, rocky sites, openings in conifer forests  +
Balsamorhiza lanata +Roadsides, grassy slopes  +
Balsamorhiza macrolepis +Open, dry or moist, grassy or rocky slopes, valleys  +
Balsamorhiza macrophylla +Deep soils, rocky meadows, sagebrush scrublands, conifer forests  +
Balsamorhiza rosea +Dry hills  +
Balsamorhiza sagittata +Openings, banks, flats, meadows, ridges, sagebrush scrub, conifer forests  +
Balsamorhiza sericea +Serpentine outcrops, among surface rocks, in crevices, hillsides, dry streamsides among cobbles  +
Balsamorhiza serrata +Basaltic scablands, sagebrush scrub, openings in forests, meadow borders  +
Barbarea orthoceras +Open grassland, sandbars, scree, alpine meadows, ledges, rocky cliffs, forests, streamsides, railroad embankment, boggy ground, gravel pits, moist grassy slopes  +
Barbarea stricta +Waste places, ditches, riverbanks, damp grasslands, roadsides, fields, disturbed sites  +
Barbarea verna +Waste grounds, fields, limestone glades, rocky outcrops, fields, railroad embankments, disturbed sites, roadsides  +
Barbarea vulgaris +Waste places, ditches, riverbanks, damp grasslands, roadsides, fields, disturbed sites  +
Barbella pendula +Deep, cool, shady, humid ravines in deciduous forests, on Arundinaria, shrubs, tree branches, exposed roots along ravines  +
Barbula amplexifolia +Rock, often limestone, occasionally sandstone, usually in moist areas, mountain slopes, cliffs, tundra, mist zone of waterfalls  +
Barbula bolleana +Wet limestone, moist areas, wet rocks  +
Barbula convoluta var. convoluta +Rock, soil, sand, thin soil on rock, gravel, lava, cement, often associated with limestone or dolomite, bricks and mortar, walls, stumps, woods, fields  +
Barbula convoluta var. eustegia +Sandy banks, soil, logs, in pine woods, shores  +
Barbula convoluta var. gallinula +Rock, usually limestone, or soil or humus  +
Barbula indica var. gregaria +Soil  +
Barbula indica var. indica +Soil, clay, limestone, cement, walls  +
Barbula orizabensis +Disintegrating rock  +
Barbula unguiculata +Soil, sand, gravel, sandstone, granite, limestone, walls, roadcuts, paths, lawns, ditches  +
Barkleyanthus salicifolius +Open, rocky, disturbed sites  +
Bartlettia scaposa +Gravelly or adobe soils, grasslands, playas  +
Bartramia brevifolia +Rock crevices, canyon ledges  +
Bartramia halleriana +Crevices of shaded cliffs, rock outcrops in humid forests  +
Bartramia ithyphylla +Soil, rock  +
Bartramia pomiformis +Soil, rock, base of trees, downed trunks, moist shady forests  +
Bartramia potosica +Cliff crevices, thin soil on canyon ledges, base of boulders  +
Bartramia stricta +Soil, rock  +
Bartramia subulata +Bare soil in montane tundra  +
Bartramiopsis lescurii +Soil banks or soil over rock, exposed tree roots  +
Bartsia alpina +Subarctic and arctic tundra, lakeshores, fens.  +
Basiphyllaea corallicola +Open pineland savannas and hammocks, in humus over limestone  +
Bassia hirsuta +Seashores, coastal dunes, salt marshes, other saline and alkaline habitats  +
Bassia hyssopifolia +Saline habitats, coastal dunes, salt marshes, disturbed habitats, roadsides, fields  +
Bastardia viscosa +Shrublands, thickets, disturbed vegetation, pastures, roadsides  +
Batesimalva violacea +Dry, deciduous forests and shrublands  +
Batis maritima +Saline or brackish, often wet, open, maritime shores, salt marshes, dune swales, saline or brackish lagoons, sandy shell plateaus, shore hummocks, muddy or sandy tidal flats, often with mangroves, especially Avicennia  +
Bebbia juncea var. aspera +Rocky and sandy soils, dry hillsides, slopes, desert washes, canyons  +
Begonia cucullata +Along streams in swamps, floodplain woodlands, cabbage palmetto hummocks, wet ditches, wet and mucky soil, often in shade  +
Begonia hirtella +Around solution holes of rockland hummocks, greenhouse weeds  +
Bejaria racemosa +Low pine flatwoods and scrub oak-saw palmetto  +
Belamcanda chinensis +Grassland, pastures, woodland clearings, disturbed limestone glades, rocky outcrops  +
Bellardia latifolia +Pastures, roadsides, open areas.  +
Bellardia trixago +Disturbed grasslands, roadsides, fields, serpentine grasslands.  +
Bellardia viscosa +Wetland prairies, fields, pastures, beach foreshores, roadsides.  +
Bellibarbula recurva +Thin soil over moist rock in protected mountain stations, forested gorges, coves, cliffs, along streams and by waterfalls  +
Bellis perennis +Lawns and moist, waste places, roadsides  +
Beloglottis costaricensis +Hammocks, in humus  +
Benitoa occidentalis +Serpentine outcrops and clay slopes  +
Bensoniella oregona +Wet meadows, bogs, shady fir forests  +
Berberis amplectens +Rocky slopes in chaparral and open forest  +
Berberis aquifolium +Open woods and shrublands  +
Berberis bealei +Open woodlands and shrublands  +
Berberis canadensis +In woods or glades, on rocky slopes and near rivers  +
Berberis darwinii +Humid areas near coast  +
Berberis dictyota +Dry rocky places in chaparral and open woodland  +
Berberis fendleri +Slopes and canyon bottoms  +
Berberis fremontii +Slopes and flats in desert grassland and pinyon-juniper woodland  +
Berberis haematocarpa +Slopes and flats in desert shrubland, desert grassland, and dry oak woodland  +
Berberis harrisoniana +Shady spots in rocky canyons  +
Berberis higginsiae +Chaparral and pinyon-juniper woodland  +
Berberis nervosa +Open or shaded woods, often in rocky areas  +
Berberis nevinii +Sandy slopes and washes in chaparral, coastal scrub, and riparian scrub  +
Berberis pinnata subsp. insularis +In shade beneath trees, pine and pine-oak forest  +
Berberis pinnata subsp. pinnata +Exposed rocky openings in woods and shrubland  +
Berberis piperiana +Open wooded and shrubby slopes  +
Berberis pumila +Open woods and rocky areas  +
Berberis repens +Open forest, shrubland, and grassland  +
Berberis swaseyi +Limestone ridges and canyons  +
Berberis thunbergii +Woods, old fields, roadsides  +
Berberis trifoliolata +Slopes and flats in grassland, shrubland, and sometimes open woodland  +
Berberis vulgaris +Roadsides, woods, old fields  +
Berberis wilcoxii +Slopes and canyons  +
Berchemia scandens +Riparian areas, ravines, swamps, bottomlands, upland forests.  +
Bergerocactus emoryi +Coastal bluff scrub, semidesert scrub, sandy soils  +
Bergia texana +Muddy or sandy shores and flats, emergent shorelines of rivers, lakes, playas, pools, ditches, ponds.  +
Berlandiera lyrata +Dry, sandy loams, rocky, limestone soils, roadsides, grasslands with mesquite, oak, and juniper  +
Berlandiera monocephala +Grasslands on rolling hills, often with oak, pinyon, and juniper  +
Berlandiera pumila +Sandy soils, roadsides, fields, woodland borders, open woodlots  +
Berlandiera subacaulis +Dry, sandy oak and pine flats, lawns, along roadsides  +
Berlandiera texana +Dry, rocky, calcareous and sandy soils, open woodlands, glades, thickets  +
Berlandiera ×betonicifolia +Sandy-loamy soils, edges of or in woodlands of oak, pine, and/or hickory  +
Berlandiera ×humilis +Sandy pine flats, openings  +
Berlandiera ×macrophylla +Calcareous outcrops and derived soils  +
Bernardia incana +Protected slopes in desert canyon washes.  +
Bernardia myricifolia +Shrub communities on rocky limestone hills in oak-juniper woodlands, thornscrub.  +
Bernardia obovata +Canyon washes in high desert scrub.  +
Berteroa incana +Flood plains, meadows, waste places, railroad embankments, woodlands, grasslands, roadsides, fields, stream banks, pastures, hillsides, forest floor  +
Bestia longipes +Rock walls, boulders, along streams, coastal mountains influenced by summer fog, basal burls of broadleaf trees, especially Umbellularia californica  +
Beta vulgaris subsp. maritima +Moist, sandy places near the coast and in waste areas  +
Beta vulgaris subsp. vulgaris +Sporadic in waste areas  +
Betula alleghaniensis +Stream banks, swampy woods, and rich, moist, forested slopes  +
Betula cordifolia +Moist, rocky slopes or rich, open forest  +
Betula glandulosa +Arctic and alpine tundra, acidic rocky slopes and barrens, muskegs, peat bogs, stream banks, open subalpine summits  +
Betula kenaica +Rocky slopes in the subalpine zone  +
Betula lenta +Rich, moist, cool forests, especially on protected slopes, to rockier, more exposed sites  +
Betula michauxii +Sphagnum bogs, around pools, and wet peaty meadows  +
Betula minor +Rocky slopes, barrens, and subalpine summits  +
Betula murrayana +Wet, swampy forests containing Betula pumila  +
Betula nana subsp. exilis +Wet tundra and margins of bogs, terraces and open slopes  +
Betula nana subsp. nana +Tundra, open rocky barrens, and scrubs, in Europe subalpine mountain moors  +
Betula neoalaskana +Rocky or peaty slopes, bog margins, sandhills, open woods  +
Betula nigra +Riverbanks and flood plains, often where land is periodically inundated  +
Betula occidentalis +Montane stream banks, slopes, and ridges, also in moist open woods, at edges of marshes, along lakeshores, and in wet swales  +
Betula papyrifera +Moist, ± open, upland forest, especially on rocky slopes, also sometimes in swampy woods  +
Betula pendula +Abandoned plantings, roadsides, edges of bogs, waste places  +
Betula populifolia +Rocky or sandy open woods, moist to dryish slopes, old fields, and waste places  +
Betula pubescens subsp. pubescens +Rocky slopes, scrubs, heaths, and open woods where native, elsewhere in abandoned plantings, moist open roadsides, swales, swampy thickets  +
Betula pubescens subsp. tortuosa +Protected inland valleys  +
Betula pumila +Bogs, calcareous fens, wooded swamps, muskegs, lake shores  +
Betula uber +Stream banks and adjacent flood plains in rich mesic forest  +
Bidens amplissima +Seasonal wetlands, borders of ponds, lakes, streams, estuaries  +
Bidens aristosa +Marshes, meadows, pine forests, disturbed sites  +
Bidens aurea +Marshes, borders of streams, other wet sites  +
Bidens beckii +Still or slow-moving waters  +
Bidens bidentoides +Borders of streams, estuaries  +
Bidens bigelovii +Along streams, other wettish sites  +
Bidens bipinnata +Fields, forests, disturbed, wettish sites  +
Bidens cernua +Swamps, marshes, peat and sedge bogs, flood plains