3.
Ratibida pinnata
(Ventenat) Barnhart, Bull. Torrey Bot. Club. 24: 410. 1897.
Grayhead or pinnate prairie coneflower
Rudbeckia pinnata
Ventenat, Descr. Pl. Nouv., plate 71. 1802
Perennials,
to 125+ cm; fibrous rooted (arising from stout rhizomes or woody caudices).
Leaves
5—40 × 3—15+ cm, pinnatifid to pinnate, lobes 3—9, narrowly lanceolate to ovate, 1—15 × 0.2—3.5 cm, faces strigose, gland-dotted.
Heads
mostly 1—12, held well beyond leaves.
Peduncles
3—27+ cm (ribs tan, prominent).
Phyllaries
10—15, outer linear, 3—15 × 1—3 mm, inner lanceolate-ovate, 3—6 × 0.7—3 mm.
Paleae
1.2—5 × 1—1.8 mm, resin glands linear to oblanceolate, 2—3.3 mm.
Ray florets
6—15; corollas yellow, 2.5—3.8 mm, tubes ca. 1—3 mm, hirsute, laminae linear-elliptic to oblong-oblanceolate, 16—60 × 4—15 mm.
Discs
ellipsoid to globular or ovoid, 10—25 × 10—18 mm.
Disc florets
100—200+; corollas greenish yellow, often purplish distally, 2.5—3.8 mm; style branches ca. 1.8 mm, proximal
1
/2 stigmatic, apices subulate.
Cypselae
linear-oblanceoloid, 2—4 × 1—2.3 mm, margins usually glabrous, sometimes adaxial ciliate;
pappi
0 or of 1—2 toothlike projections.
2
n
= 28.
Flowering May—Oct. Prairies, woodland openings and borders, limestone outcrops; 10—300 m; Ont.; Ala., Ark., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Mass., Mich., Minn., Miss., Mo., Nebr., N.Y., Ohio, Okla., S.Dak., Tenn., Vt., Wis.
