196 
Spring Flora of Oklahoma 
XIV. RUDBECKIA L. 
Perennial or biennial. Leaves alternate, entire or lobed. 
Heads radiate, long peduncled, many-flowered. Bracts im¬ 
bricated in 2-3 series, spreading. Receptacle convex or 
long-conical, with concave, chaffy sales. Ray-flowers yellow, 
neutral. Disk-flowers purple to brown, bi-sexual. Achenes 
smooth 4-angled, truncate. Pappus a few short teeth or 
wanting. 
1. Rudebeckia hirta L. Black Eyed Susan. Biennial or 
sometimes annual, hirsute or hispid throughout. Stems l°-3° high. 
Leaves sparingly serrate with low teeth, or entire, lanceolate or ob¬ 
long 3 to 5 nerved. Heads commonly few or solitary, 2'-4' broad. 
Rays 10-20, orange or orange-yellow. Bracts of the involucre very 
hirsute, spreading or reflexed. Disk globose-ovoid, purple-brown. 
Chaff of the receptacle linear, hirsute at the apex. Pappus none. 
Prairies and plains. May-September. Common. 
X\. DRACOPIS Cass. 
An annual, caulescent herb, with smooth and glaucous 
foliage, and alternate broad, thickish, entire or slightly 
serrate, 1-ribbed, clasping leaves. Involucre flat, of few, 
narrow, foliaceous bracts. Receptacle slender, with early, 
deciduous, chaffy scales. Ray-flowers few, neutral, yellow. 
Disk flowers perfect, fertile, brownish. Achenes terete or 
nearly so, not angled, striate and transversely wrinkled. 
Pappus wanting. 
1. Dracopis amplexicaulis (Vahl.) Cass. Clasping-leaved Cone- 
flower. Annual. Glabrous throughout, somewhat glaucous. Stem 
branched grooved, 12'-24' high. Leaves entire or sparingly toothed, 
1-ribbed, reticulate-veined, the lower oblong to spatulate, sessile, the 
upper ovate or lanceolate, cordate-clasping. Heads solitary, about 
2' broad. Bracts of the involucre few, lanceolate. Rays yellow, or 
sometimes brown at the base. Disk ovoid-oblong, often becoming 
1' high. 
In wet soil. May-August. Common. 
XVI. RATIBIDA Raf. 
Perennial herbs. Leaves alternate, pinnately divided. 
Heads radiate, long-peduncled, many-flowered. Involucral 
bracts in 2 or 3 series. Disk globose. Receptacle columnar 
