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brown-eyed susan, thin-leaf coneflower, three-leaf coneflower, three-lobed coneflower

Photo is of parent taxon

browneyed susan

Habit Perennials, to 150 cm (rhizomatous).
Stems

glabrate to hirsute or strigose (hairs 1–2 mm, basal retrorse, others spreading).

Leaves

blades ovate to subcordate or elliptic (not lobed), margins serrate, apices acute to acuminate, faces hirsute to strigose;

basal petiolate, 10–30 × 2–8 cm, bases truncate or rounded to cordate;

cauline petiolate or sessile, ovate to elliptic, proximal usually 3–5-lobed, 2–20 × 1.5–8 cm (smaller, fewer lobed distally), bases rounded to attenuate, sometimes clasping.

Cauline leaves

(at least some) 3-lobed.

Receptacles

conic to subhemispheric;

paleae 5–6.5 mm, apices cuspidate (tips awnlike, 1.5+ mm), glabrous.

Ray florets

8–15;

laminae (corollas yellow to yellow-orange with basal maroon splotches) linear to oblanceolate, 8–30 × 3–8 mm, abaxially sparsely strigose.

Ray laminae

8–17 mm.

Disc florets

150–300+;

corollas yellowish green basally, otherwise brown-purple, 3–4 mm;

style branches ca. 1.2 mm, apices obtuse to rounded.

Phyllaries

to 1.5 cm (faces moderately hirsute).

Heads

(10–30) in paniculiform arrays.

Cypselae

1.9–2.8 mm;

pappi coroniform, to 0.2 mm.

Discs

8–15 × 10–20 mm.

10–15 mm diam.

2n

= 38, ca. 57, 57.

Rudbeckia triloba

Rudbeckia triloba var. triloba

Phenology Flowering Jul–Oct.
Habitat Mesic to wet woodlands, thickets, pastures, roadsides, meadows
Elevation 20–300 m (100–1000 ft)
Distribution
from FNA
AL; AR; CO; CT; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MS; NC; NE; NJ; NY; OH; OK; PA; TN; TX; UT; VA; VT; WI; WV; ON; QC
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CO; CT; DE; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MS; NC; NE; NJ; NY; OH; OK; PA; TN; TX; UT; VA; VT; WI; WV; ON; QC
[BONAP county map]
Discussion

Varieties 3 (3 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Variety triloba is introduced in Canada.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Cauline leaves (at least some) 5–7-lobed (Florida, Kentucky, North Carolina, Virginia)
var. pinnatiloba
1. Cauline leaves (at least some) 3-lobed
→ 2
2. Ray laminae 8–17 mm; discs 10–15 mm diam. (20–100 m; relatively widespread)
var. triloba
2. Ray laminae 18–30 mm; discs 15–20 mm diam. (100–1200 m; Iowa, Kentucky, North Carolina, Tennessee)
var. rupestris
Source FNA vol. 21, p. 59. FNA vol. 21, p. 60.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Rudbeckiinae > Rudbeckia > sect. Rudbeckia Asteraceae > tribe Heliantheae > subtribe Rudbeckiinae > Rudbeckia > sect. Rudbeckia > Rudbeckia triloba
Sibling taxa
R. alpicola, R. amplexicaulis, R. auriculata, R. californica, R. fulgida, R. glaucescens, R. graminifolia, R. grandiflora, R. heliopsidis, R. hirta, 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 var. pinnatiloba, R. triloba var. rupestris
Subordinate taxa
R. triloba var. pinnatiloba, R. triloba var. rupestris, R. triloba var. triloba
Synonyms R. beadlei, R. triloba var. beadlei
Name authority Linnaeus: Sp. Pl. 2: 907. (1753) unknown
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