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Rudbeckia grandiflora
(Sweet) C. C. Gmel. ex DC.
Family:
Asteraceae
Rough Coneflower
FNA
Gleason & Cronquist
Resources
Lowell E. Urbatsch, Patricia B. Cox in Flora of North America (vol. 21)
Perennials,
to 120 cm (roots fibrous, caudices often woody).
Stems
proximally glabrous or sparsely hairy (hairs spreading), distally strigose (hairs ascending).
Leaves:
blades elliptic, lanceolate, or ovate (± conduplicate, not lobed), bases cuneate to rounded, margins entire or remotely serrate, apices acute, faces strigose, abaxially gland-dotted; basal petiolate, 10-35 × 2-11 cm; cauline petiolate (proximal) to nearly sessile (distal), 4-30 × 1.5-9 cm.
Heads
mostly borne singly.
Phyllaries
to 15 mm (strigose and gland-dotted).
Receptacles
hemispheric to ovoid; paleae 5-6.5 mm, (apical margins glabrous) acuminate-cuspidate, awn-tipped, abaxial tips sparsely strigose.
Ray florets
12-25; laminae elliptic to obovate (reflexed), 20-50 × 5-10 mm, abaxially hairy and gland-dotted.
Discs
10-30 × 15-25 mm.
Disc florets
200-800+; corollas greenish yellow basally and in lobes, otherwise maroon, 3.5-5 mm; style branches ca. 1.8 mm, apices obtuse.
Cypselae
2-3 mm;
pappi
coroniform, to 0.5 mm.
Vascular plants of NE US and adjacent Canada
An Ozarkian sp. with larger heads (rays 3-5 cm) and with the lvs hirsute on both sides, barely enters our range in c. Mo. as an introduction.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
©The New York Botanical Garden. All rights reserved. Used by permission.
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