Rudbeckia sect. Rudbeckia
Annuals, biennials, or perennials, to 100(–200) cm (rhizomatous, fibrous rooted, or taprooted). Stems green. Leaves green, not glaucous; basal (usually withering before flowering) usually petiolate, blades linear, lanceolate to ovate, or elliptic to oblanceolate, sometimes lobed, bases attenuate, cuneate, or rounded, margins entire, dentate, or serrate, apices acute to obtuse, faces glabrous or hairy, sometimes gland-dotted; cauline usually petiolate (at least proximal), distal usually sessile, blades linear or ovate to pandurate, sometimes lobed, lobes 3(–5), bases auriculate, attenuate, or cordate, margins entire or serrate, apices acute to obtuse, faces glabrous or hairy, sometimes gland-dotted. Heads borne singly or in loose, corymbiform to paniculiform arrays. Phyllaries in 2(–3) series. Receptacles usually conic to hemispheric, rarely columnar; paleae surpassing cypselae, margins sometimes ciliate, apices obtuse or rounded to acute or attenuate to apiculate, faces glabrous or hairy abaxially. Ray florets 6–25+; corollas usually yellow-orange proximally, yellow distally, sometimes with basal maroon splotch (orangish red to maroon in R. graminifolia). Discs 8–30 × 5–25 mm. Disc florets 50–800+; corollas proximally yellow to yellowish green, distally usually brown-purple, lobes sometimes yellowish or greenish; anther appendages sometimes gland-dotted; styles 3–5+ mm, branches 1–1.8 mm, proximal 1/2–4/5 stigmatic, apices acute to rounded. Cypselae 1.5–3.5(–4) mm; pappi usually coroniform (sometimes cypselae each with glandular hairs around apices in R. heliopsidis). x = 19.
e North America.
Species 9 (9 in the flora).
|1||Leaves 0.2–1 cm wide (grasslike, lengths 10+ times widths); rays orangish red to maroon; Florida panhandle||Rudbeckia graminifolia|
|1||Leaves (0.4–)1–15 cm wide (if less than 1 cm wide, lengths less than 10 times widths); rays yellow to yellow-orange (at least distally); e North America||> 2|
|2||Annuals, biennials, or perennials (taprooted or roots fibrous); pappi 0 or coroniform (to 0.1 mm)||> 3|
|2||Perennials (usually rhizomatous and/or stoloniferous, roots fibrous, caudices sometimes woody); pappi 0 or coroniform (0.1–0.5 mm; sometimes cypselae each with glandular hairs around apices in R. heliopsidis)||> 4|
|3||Stems and leaves coarsely hispid to hirsute; style branch apices subulate; e NorthAmerica||Rudbeckia hirta|
|3||Stems and leaves softly pilose to woolly; style branch apices acute to obtuse; Alabama, Florida, Georgia, South Carolina||Rudbeckia mollis|
|4||Proximal cauline leaves elliptic or ovate, usually 3(–5)-lobed; paleae cuspidate (tips awnlike, 1.5+ mm)||Rudbeckia triloba|
|4||Proximal cauline leaves elliptic, linear, spatulate, or ovate, rarely lobed (3–5–lobed in R. subtomentosa); paleae acute, obtuse, or rounded||> 5|
|5||Stems and leaves densely hirsute; proximal cauline leaves 3(–5)–lobed; heads (usually 8–25) in loose, corymbiform to paniculiform arrays||Rudbeckia subtomentosa|
|5||Stems and leaves glabrous or sparsely to moderately hairy; proximal cauline leaves not lobed; heads borne singly or (2–12) in corymbiform arrays||> 6|
|6||Leaves: abaxial faces glabrous or hirsute to strigose (not gland-dotted); paleae: abaxial tips usually glabrous, rarely pilose||> 7|
|6||Leaves: abaxial faces glabrous or strigose and gland-dotted; paleae: abaxial tips canescent or strigose, sometimes gland-dotted as well||> 8|
|7||Plants stoloniferous (rosettes forming at stolon apices; stem branches spreading); basal leaves lanceolate to broadly ovate or elliptic||Rudbeckia fulgida|
|7||Plants not stoloniferous (rosettes at bases of aerial stems; stem branches ascending); basal leaves linear to narrowly spatulate||Rudbeckia missouriensis|
|8||Leaf blades elliptic, lanceolate, or ovate (flat); heads usually (4–8) in ± corymbiform arrays, sometimes borne singly; rays 6–12 (± spreading); pappi coroniform, to 1.5 mm (sometimes cypselae each with glandular hairs around apices); Alabama, Georgia, North Carolina, South Carolina, Virginia||Rudbeckia heliopsidis|
|8||Leaf blades elliptic, lanceolate, or ovate (± conduplicate); heads usually borne singly; rays 12–25 (reflexed); pappi coroniform, to 0.5 mm; midwestern and sc United States||Rudbeckia grandiflora|