Rudbeckia triloba
Rudbeckia nitida
brown-eyed susan, thin-leaf coneflower, three-leaf coneflower, three-lobed coneflower
shiny coneflower, St. John's or black-eyed susan
glabrate to hirsute or strigose (hairs 1–2 mm, basal retrorse, others spreading).
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.
green (lightly glaucous), blades elliptic to lanceolate (not lobed), leathery, bases attenuate to cuneate, margins crenate, entire, or toothed, apices acute, faces glabrous or sparsely hairy;
basal petiolate, 15–60 × 2–8 cm;
cauline petiolate or sessile, 5–50 × 2–9 cm.
conic to subhemispheric;
paleae 5–6.5 mm, apices cuspidate (tips awnlike, 1.5+ mm), glabrous.
ovate to columnar;
paleae (recurved prior to flowering, erect to spreading in young heads) 5–6 mm, apices acute to acuminate, abaxial tips hairy.
8–15;
laminae (corollas yellow to yellow-orange with basal maroon splotches) linear to oblanceolate, 8–30 × 3–8 mm, abaxially sparsely strigose.
8–15;
laminae oblong to oblanceolate, 12–60 × 5–15 mm, abaxially sparsely hairy.
150–300+;
corollas yellowish green basally, otherwise brown-purple, 3–4 mm;
style branches ca. 1.2 mm, apices obtuse to rounded.
200–300+;
corollas yellowish green proximally, maroon distally, 3.5–4.5 mm;
style branches ca. 1.2 mm, apices acute to acuminate.
to 1.5 cm (faces moderately hirsute).
to 2 cm (margins sometimes ciliate, sparsely hairy).
(10–30) in paniculiform arrays.
borne singly or in ± corymbiform arrays.
1.9–2.8 mm;
pappi coroniform, to 0.2 mm.
3–5.5 mm;
pappi ± coroniform, to 2 mm.
8–15 × 10–20 mm.
10–30 × 12–20 mm.
= 36.
Rudbeckia triloba
Rudbeckia nitida
Varieties 3 (3 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Of conservation concern.
Rudbeckia nitida grows in northern Florida and southern Georgia (a report for Alabama has not been confirmed). It is cultivated as an ornamental. According to R. Kral (1983), it is threatened or endangered and is associated with savanna or bog dicots and monocots, particularly Eriocaulon, Sarracenia, Lachnocaulon, Rhexia, Xyris, and the composites Coreopsis, Helianthus, and Liatris.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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 |
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