Bull. Sci. Soc. Philom. Paris 1817: 137. 1817.
Annuals or perennials, (5–)30–60(–200) cm (sometimes becoming shrubby through shoot persistence, with camphor odor when leaves moderately to densely stipitate-glandular); stout taprooted or with woody caudices, sometimes also rhizomatous. Stems ascending-erect, branched distally, appressed-strigose and hispid, sparsely to abundantly long-hispid or -hirsute (hairs spreading, long, cells osteolate, walls minutely pustulate). Leaves basal and cauline; petiolate (petiole basal margins always coarsely, spreading-ciliate) or sessile; proximal blades 1-nerved, ovate-oblanceolate (bases tapering), hairy; distal smaller (bases sometimes clasping), margins (sometimes undulate) serrate to entire, faces hispid to strigose, stipitate-glandular. Heads radiate (discoid in H. oregona), borne singly or in corymbiform arrays, sometimes becoming paniculiform. Involucres campanulate to turbinate (campanulo-hemispheric upon drying), (3–14 ×) 3.8–23 mm. Phyllaries 26–80 in 3–5 series, 1-nerved (usually raised; keeled proximally), lanceolate to linear-lanceolate, usually strongly unequal (usually stiff), margins scarious (sometimes distally reddish purple), sparsely to densely strigose (hairs short to long), eglandular to densely stipitate-glandular (usually more densely so distally). Receptacles slightly convex, subulate, pitted, epaleate. Ray florets (4–)30 (0 in H. oregona), pistillate, fertile; corollas yellow (tubes glabrate to short-pilose, laminae usually eglandular, sometimes stipitate-glandular proximally). Disc florets 9–110; corollas yellow, ampliate, tubes shorter than narrowly funnelform throats (glabrate to sparsely, minutely strigose, hairs 0.5–1.5 mm in 2 species, sometimes minutely glandular), lobes 5, erect to spreading, deltate, triangular, or lanceolate; style-branch appendages narrowly triangular. Cypselae sometimes dimorphic, obconic, compressed or not, of ray florets often 3-angled, 4–12-ribbed, faces glabrous or densely strigillose; pappi 0 or in 3–4 series, outer of 3–40 (sometimes obscure) linear to linear-lanceolate or triangular scales (0.2–1 mm), inner of 30–45 off-white, stramineous, or tan to rusty brown, barbellate, apically clavate or attenuate bristles (3–11 mm). x = 9.
North America, Mexico.
Species 28 (17 in the flora).
The generic limits of Heterotheca used here are those of J. C. Semple et al. (1980), who included all goldenasters with stiff, gradually tapering, multicellular hairs with bone-shaped cells with knobby faces, regardless of whether or not they had dimorphic cypselae. Traditionally, only dimorphic species had been included. L. H. Shinners (1951e) found that some individuals of the H. subaxillaris complex sensu G. L. Nesom (1990e) are not consistently dimorphic. He thus proposed merging the genus Chrysopsis, including Pityopsis, into Heterotheca. V. L. Harms (1965) reported cytologic evidence supporting this merger and followed Shinners in subsequent papers (e.g., Harms 1970). Semple (1977) and Semple et al. (1980) presented evidence that Chrysopsis and Pityopsis differ sufficiently to be treated as separate genera based on habit, hair, leaf, cypsela, and cytologic traits. Nesom (2000) recognized Heterotheca as delimited here, following Semple et al. (1980) and Semple (1996). Semple and J. L. A. Hood (2005) showed that the assumed 2-seriate pappus was usually 3- and sometimes 4-seriate, the longest inner series usually weakly clavate apically.
The genus is divided into three sections based on ray floret presence or absence, monomorphic or dimorphic cypselae, and, to a lesser extent, leaf traits (J. C. Semple 1996). Heterotheca sect. Heterotheca has dimorphic cypselae: the ray cypselae are usually glabrous and lack pappi. B. L. Wagenknecht (1960) revised section Heterotheca; G. L. Nesom (1990e) proposed an alternative treatment and combined several annual species. The latter is followed here with slight modification: three species are recognized (two in the flora, H. grandiflora and H. subaxillaris). The monospecific sect. Ammodia (Nuttall) V. L. Harms has discoid heads. Semple et al. (1988) revised sect. Ammodia and presented a multivariate analysis of the single species, H. oregona. The large sect. Phyllotheca (Nuttall) V. L. Harms has monomorphic cypselae in radiate heads (with the exception of one Mexican species). Semple (1996) revised sect. Phyllotheca (the C. villosa complex in the broad sense) and summarized data on the goldenaster genera. Species of sect. Phyllotheca are often difficult to distinguish due to a combination of environmentally induced plasticity, overlap in ranges of characters, and subtlety of diagnostic traits; most species include a wide range of indument types. Most taxa in this section have been included in Chrysopsis villosa (Pursh) Nuttall at one time or another by various authors. As treated by Semple (1996), the section consists of five species complexes: the sessiliflora complex native to California [H. sessiliflora, H. monarchensis, and Mexican H. thiniicola (Rzedowski & E. Ezcurra) B. L. Turner]; the mexicana complex [four Mexican species: H. brandegeei (B. L. Robinson & Greenman) Semple, H. gypsophila B. L. Turner, H. mexicana V. L. Harms ex B. L. Turner, and H. mucronata V. L. Harms & B. L. Turner]; the fulcrata complex of the southern Rocky Mountains (H. fulcrata, H. marginata, H. pumila, H. rutteri, and H. viscida); the Great Plains stenophylla complex (H. canescens, H. stenophylla); and the transcontinental villosa complex (H. barbata, H. camporum, H. jonesii, H. shevockii, H. villosa, and H. zionensis).
The common name “false goldenaster” appears to have been arbitrarily coined recently and subsequently used on the plants.usda.gov web site, as are many of the common names listed for species. Historically, the common names “camphorweed” or “telegraph weed” were applied to the taxa with dimorphic cypselae, while “goldenaster” or “golden aster” was applied to the taxa with monomorphic cypselae (i.e., those that had been included in Chrysopsis in the broad sense). The common name “goldenaster” is preferred and was used in Semple (1996).
Semple, J. C., V. Blok, and P. Heiman. 1980. Morphological, anatomical, habit, and habitat differences among the goldenaster genera Chrysopsis, Heterotheca and Pityopsis (Compositae–Astereae). Canad. J. Bot. 58: 147–163.
Semple, J. C., C. Leeder, C. Leuty, and L. Gray. 1988. Heterotheca sect. Ammodia (Compositae: Astereae): A multivariate study of H. oregona and specimens of Brewer’s (golden)aster. Syst. Bot. 13: 547–558.
|1||Pappi of ray and disc florets different (heads radiate); annuals, rarely perennials (sect. Heterotheca)||> 2|
|1||Pappi of ray and disc florets similar or heads discoid; perennials||> 3|
|2||Stems procumbent to erect, proximal to distal branches well developed in larger plants; distal leaves and larger bracts ovate to lanceolate; heads in corymbo-paniculiform arrays, becoming loosely paniculiform or broadly corymbiform in larger plants||Heterotheca subaxillaris|
|2||Stems ascending to erect (strict), only distal branches developing in larger plants (atypical, spring-blooming, dwarf dune plants have short stems); distal leaves and larger bracts oblong-lanceolate to lanceolate or linear-lanceolate; heads in corymbiform, becoming paniculiform arrays (branches ascending, never widely spreading; California, adjacent Arizona, sw Utah)||Heterotheca grandiflora|
|3||Heads discoid; short outer pappus bristles relatively few, obscure; Pacific coast (sect. Ammodia)||Heterotheca oregona|
|3||Heads radiate; short outer pappi usually obvious, sometimes obscure; w North America (sect. Phyllotheca)||> 4|
|4||Corolla throats and/or lobes sparsely hairy (sometimes obscurely so, longest hairs usually 0.2–1 mm); leaf margins often undulate; California, coastal nw Baja California (Mexico)||> 5|
|4||Corolla throats and/or lobes glabrous or sparsely hairy (longest hairs to 0.3 mm, to 0.5 mm in H. rutteri); leaf margins usually not very undulate; North America||> 6|
|5||Stems (10–)20–70(–100) cm; distal leaf blades narrowly to broadly lanceolate (if oblanceolate then corolla lobe hairs 0.1–1 mm, obvious), usually reduced distally, bases rounded, faces sparsely to densely hispido-strigose or short-strigose, sparsely to densely stipitate-glandular; California, nw Baja California (Mexico)||Heterotheca sessiliflora|
|5||Stems 9–17.5 cm; distal leaf blades narrowly oblanceolate, faces moderately to densely hispido-strigose, sparsely stipitate-glandular; corolla lobe hairs 0.2–0.6 mm; Fresno County, California||Heterotheca monarchensis|
|6||Stems 2.3–6 cm, usually decumbent (dwarf cushion plants, often buried in sand); distal cauline leaves oblanceolate, (3.5–)5–10 × 1.1–2.4(–3.2) mm, faces eglandular; heads borne singly; peduncles 3–5 mm (sandy pockets in sandstone cliffs, sw Utah)||Heterotheca jonesii|
|6||Stems (7–)12.5–110(–150) cm, decumbent to erect (not dwarf cusion plants); distal cauline leaves oblong, lanceolate, oblanceolate, elliptic, or ovate, (4–)15–65 × 1.5–15 mm, faces eglandular or sparsely to densely stipitate-glandular; heads 1–50; peduncles 1–60+ mm.||> 7|
|7||Stems ascending to erect; distal leaf blades narrowly ovate to lanceolate, apices sharply acute, faces densely long-strigose (silvery white), sparsely stipitate-glandular; grassy plains, s Arizona, Mexico||Heterotheca rutteri|
|7||Stems decumbent to erect; distal leaf blades linear-triangular or lanceolate to ovate or obovate, apices acute to obtuse, faces sparsely to densely strigose or densely strigoso-canescent (silvery white), eglandular or sparsely to densely stipitate-glandular; w North America||> 8|
|8||Mid to distal cauline leaves lanceolate to ovate, faces sparsely hispido-strigose, moderately to densely stipitate-glandular; heads (1–7 per stem) on peduncles 10–36 mm, without immediately subtending bracts (se Arizona, trans-Pecos Texas, Mexico)||Heterotheca viscida|
|8||Mid to distal cauline leaves either linear-oblanceolate or linear-lanceolate, lanceolate to broadly oblanceolate, or oblong, if ovate or obovate then heads usually not borne singly on well-defined peduncles, sometimes with immediately subtending, large, obovate bracts||> 9|
|9||Margins of distal leaves usually hispido-strigose; some or all heads subtended by 1+ ovate to lanceolate leaflike bracts, distinct from distal leaves and usually surpassing heads, obscure in narrow-leaved, hairy plants (c Rocky Mountains to n Mexico)||Heterotheca fulcrata|
|9||Margins of distal leaves usually long-hispido-strigose only proximally, or if along whole margin then leaf blades oblanceolate, linear-oblanceolate, linear-elliptic, or linear-oblong, not ovate; heads sometimes subtended by linear to oblanceolate, leaflike bracts, not by ovate-lanceolate bracts||> 10|
|10||Plants 40–80 cm, often with long, ascending lateral branches; herbage (stems, leaf margins, peduncles, bracts) abundantly long-hispido-strigose; distal leaves stiff, blades oblanceolate, faces coarsely hispido-scabrous, sparsely stipitate-glandular; Pinal and Superstition mountains, s Arizona||Heterotheca marginata|
|10||Plants (7–)12.5–110(–150) cm, if taller than 40 cm then not from the Pinal and Superstition mountains, Arizona; herbage may be long-hirsute but not on most parts; distal leaves usually not stiff, linear-lanceolate, lanceolate, elliptic, oblong, or ovate, faces sparsely to densely strigose (silvery-whitish to whitish), sparsely to densely stipitate-glandular; w North America, e United States along roadsides and disturbed areas||> 11|
|11||Distal leaves strongly ascending to spreading, blades narrowly to linearly oblanceolate (rarely broader), distal margins usually long-ciliate; proximal stems often brittle, brown to dark brown; axillary fascicles of leaves often present (c, s Great Plains)||> 12|
|11||Distal leaves usually spreading, sometimes perpendicular, blades usually oblong, oblanceolate, or lanceolate, rarely obovate or ovate, not linear-oblanceolate (except H. pumila, 2900–3800 m, c Rocky Mountains), distal margins not long-ciliate; proximal stems not very brittle when fresh, green, white, or reddish to brown; axillary fascicles rare or absent||> 13|
|12||Distal stems strigoso-canescent, usually with few, long-hispid hairs; distal leaves ascending, congested, distal margins not long-hipido-strigose, margins faces very densely strigoso-canescent (90–200 hairs/mm²; silvery whitish), eglandular; long, linear-oblanceolate bracts often subtending heads||Heterotheca canescens|
|12||Distal stems sparsely to densely long-hispid; distal leaves usually ascending and surpassing heads, distal margins often long-hispido-strigose, faces either sparsely to moderately strigose (2–65 hairs/mm²; bright green to grayish green) and moderately stipitate-glandular or moderately strigose and eglandular||Heterotheca stenophylla|
|13||Cauline leaf margins sparsely serrate; bluffs of Mississippi River, n Ozark Mountains, disjunct eastward||Heterotheca camporum|
|13||Mid and distal cauline leaf margins entire, proximal sometimes with 1–2 distal teeth; mountains and prairies, sw Canada to Mexico.||> 14|
|14||Stems and leaves densely hispido-strigose (leaves 60–180 hairs/mm²; whitish when fresh, drying grayish to whitish green); distal leaves moderately to densely stipitate-glandular beneath hairs; peduncles moderately to densely hispido-strigose, moderately to densely glandular; phyllaries either sparsely hispido-strigose and densely stipitate-glandular or moderately hispido-strigose and sparsely to moderately stipitate-glandular [see also H. villosa var. pedunculata]||Heterotheca zionensis|
|14||Stems and leaves sparsely to moderately short-strigose or if densely strigose (leaves 80–200+ hairs/mm²) then not stipitate-glandular beneath hairs; leaf and phyllary indument similar or phyllaries less stipitate-glandular than leaves||> 15|
|15||Distal cauline leaves linear-oblanceolate, often longer then proximal, surpassing short-pedunculate heads, faces moderately strigose, sparsely to moderately stipitate-glandular; heads 1–9(–20); rays (8–)10–15 mm; alpine, 2800–3800 m., Colorado, rare in Wyoming, se Utah||Heterotheca pumila|
|15||Distal cauline leaves lanceolate, oblanceolate, or oblong, or linear-lanceolate to lanceolate-triangular, not longer then mid, usually not surpassing short- to long-pedunculate heads, faces sparsely to densely hispido-strigose, eglandular or sparsely to densely stipitate-glandular; heads 1–20(–70); rays (3.5–)5–11(–20) mm; prairies and below alpine zone in mountains, c, w North America||> 16|
|16||Plants (5–)16–40(–70) cm; distal leaves usually lanceolate or oblanceolate to oblong, rarely ovate (if lanceolate-triangular then not revolute), faces sparsely to densely hispido-strigose, sparsely to densely stipitate-glandular; inner pappus bristles equaling or longer than corollas; w mountains, Great Plains||Heterotheca villosa|
|16||Plants (28–)50–131 cm (spring-blooming plants are short); distal cauline linear-lanceolate to leaves lanceolate-triangular, margins usually revolute, faces sparsely to moderately long-hispido-strigose, moderately to densely stipitate-glandular; inner pappus bristles equaling or shorter than corollas; Kern River, California [short plants similar to H. villosa var. scabra]||Heterotheca shevockii|