Rudbeckia subtomentosa |
Rudbeckia hirta |
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sweet coneflower |
black-eyed coneflower, black-eyed susan |
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Habit | Perennials, to 200 cm (rhizomatous, rhizomes stout). | Annuals, biennials, or perennials, to 100 cm (taprooted or roots fibrous). | ||||||||||||
Stems | densely hirsute (hairs mostly antrorse, to 0.5 mm). |
hispid to hirsute (hairs spreading, 1+ mm). |
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Leaves | blades ovate to elliptic (not lobed), margins denticulate to serrate, apices acute to obtuse or acuminate, faces densely hirsute and gland-dotted (glands fewer adaxially); basal 15–30 × 3–10 cm, bases attenuate; cauline petiolate, ovate to elliptic, proximal 3–25 × 1–15 cm, usually 3–5-lobed, bases truncate to cuneate or rounded. |
blades elliptic, lanceolate, or ovate (not lobed), bases attenuate to cuneate, margins entire or serrate, apices acute, faces hispid to hirsute; basal petiolate, blades 8–30 × 0.5–7 cm; cauline petiolate or sessile, blades (sometimes pandurate) 3–20 × 0.4–4 cm. |
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Receptacles | conic to hemispheric; paleae 4–6 mm, apices acute, abaxial tips hirsute and gland-dotted. |
hemispheric to ovoid; paleae 4–6 mm, apices acute, often attenuate, abaxial tips hirsute to hispid. |
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Ray florets | 10–16; laminae (yellow to yellow-orange) linear to oblanceolate, 20–40 × 5–8 mm, abaxially sparsely hairy, abundantly gland-dotted. |
8–16; laminae (usually uniformly yellow to yellow-orange or with a basal maroon splotch, sometimes mostly maroon) elliptic to oblong or oblanceolate, 15–45 × 5–10 mm, abaxially hispid to hirsute. |
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Disc florets | 200–400+; corollas yellowish green on basal 1/2, otherwise brown-purple, 3–4.2 mm; style branches ca. 1 mm, apices acute. |
250–500+; corollas proximally yellowish green, distally brown-purple, 3–4.2 mm; style branches ca. 1.5 mm, apices subulate. |
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Phyllaries | to 1.5 cm (faces hairy and ± gland-dotted). |
to 3 cm (faces hispid to hirsute). |
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Heads | (8–25) in loose, corymbiform to paniculiform arrays. |
borne singly or (2–5) in loose, corymbiform arrays. |
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Cypselae | 2–3.5 mm; pappi coroniform, to ca. 0.2 mm. |
1.5–2.7 mm; pappi 0. |
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Discs | 10–17 × 5–15 mm. |
12–22 × 10–20 mm. |
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2n | = 38. |
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Rudbeckia subtomentosa |
Rudbeckia hirta |
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Phenology | Flowering late summer–fall. | |||||||||||||
Habitat | Mesic to wet prairies, stream banks, and woodland openings | |||||||||||||
Elevation | 20–300 m (100–1000 ft) | |||||||||||||
Distribution |
AR; CT; IA; IL; IN; KS; KY; LA; MA; MI; MO; MS; NC; NY; OK; TN; TX; WI
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AL; AR; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; ND; NE; NH; NJ; NM; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NF; NS; ON; PE; QC; SK
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Discussion | Rudbeckia subtomentosa is often cultivated as an ornamental. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 4 (4 in the flora). Some strains of Rudbeckia hirta are cultivated and/or used in seed mixes for “re-naturalization” and erosion control. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 21, p. 59. | FNA vol. 21, p. 57. | ||||||||||||
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Rudbeckiinae > Rudbeckia > sect. Rudbeckia | Asteraceae > tribe Heliantheae > subtribe Rudbeckiinae > Rudbeckia > sect. Rudbeckia | ||||||||||||
Sibling taxa | ||||||||||||||
Subordinate taxa | ||||||||||||||
Name authority | Pursh: Fl. Amer. Sept. 2: 575. (1813) | Linnaeus: Sp. Pl. 2: 907. (1753) | ||||||||||||
Web links |
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