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black-eyed coneflower, black-eyed susan

Habit Annuals, biennials, or perennials, to 100 cm (taprooted or roots fibrous).
Stems

hispid to hirsute (hairs spreading, 1+ mm).

Leaves

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.

Receptacles

hemispheric to ovoid;

paleae 4–6 mm, apices acute, often attenuate, abaxial tips hirsute to hispid.

Ray florets

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.

Disc florets

250–500+;

corollas proximally yellowish green, distally brown-purple, 3–4.2 mm;

style branches ca. 1.5 mm, apices subulate.

Phyllaries

to 3 cm (faces hispid to hirsute).

Heads

borne singly or (2–5) in loose, corymbiform arrays.

Cypselae

1.5–2.7 mm;

pappi 0.

Discs

12–22 × 10–20 mm.

Rudbeckia hirta

Distribution
from FNA
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

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.)

Key
1. Annuals, biennials, or perennials; stems branched at bases or proximal to or at or near mid heights, leafy mostly toward bases (leaves smaller distally); peduncles usually at least 1/2 plant heights (Gulf Coastal Plain, Florida to Texas)
→ 2
1. Biennials or perennials; stems branched mostly beyond mid heights, leafy ± throughout; peduncles to 1/3 plant heights
→ 3
2. Stems branched mostly at or near mid heights; basal leaves oblanceolate, faces hispid to ± sericeous; Georgia to Texas
var. angustifolia
2. Stems branched at or near bases (plants often scapiform); basal leaves obovate to nearly orbiculate, faces scabrous to hirsute; c, s Florida
var. floridana
3. Leaves: basal blades broadly ovate to broadly elliptic, 2.5–7 cm wide (lengths mostly 2 times widths), margins coarsely toothed; cauline (sometimes sessile) lanceolate, ovate, or pandurate (mostly Appalachian Highlands toIllinois)
var. hirta
3. Leaves: basal blades lanceolate to oblanceolate, 1–2.5(–5) cm wide (lengths 3–5 times widths), margins entire or serrulate; cauline blades spatulate, oblanceolate, or broadly linear
var. pulcherrima
Source FNA vol. 21, p. 57.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Rudbeckiinae > Rudbeckia > sect. Rudbeckia
Sibling taxa
R. alpicola, R. amplexicaulis, R. auriculata, R. californica, R. fulgida, R. glaucescens, R. graminifolia, R. grandiflora, R. heliopsidis, R. klamathensis, R. laciniata, R. maxima, R. missouriensis, R. mohrii, R. mollis, R. montana, R. nitida, R. occidentalis, R. scabrifolia, R. subtomentosa, R. texana, R. triloba
Subordinate taxa
R. hirta var. angustifolia, R. hirta var. floridana, R. hirta var. hirta, R. hirta var. pulcherrima
Name authority Linnaeus: Sp. Pl. 2: 907. (1753)
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