Spring Flora of Oklahoma 
199 
Rays inconspicuous, or none; awns longer than the 
width of the achene; perennial. 2. T. gracile. 
2. Thelesperma trifidum (Poir.) Britton. Fine-leaved Tiiel- 
esperma. Annual or biennial. Stem l°-3° high. Leaves numer¬ 
ous, bi-pinnately divided into filiform segments. Heads several or 
numerous, 12"-15" broad. Outer bracts of the involucre about 8, 
subulate-linear, equaling or more than half as long as the inner, 
which are united not higher than the middle. Rays 6-10, somewhat 
spatulate, 3-lobed. Disk purple or brown. 
In dry soil. May-August. Frequent. 
3. Thelesperma gracile (Torr.) A. Gray. Rayless Thelesperma. 
Perennial from a deep root. Stem l°-3° high. Leaves pinnately or 
bi-pinnately divided into linear segments. Heads 6"-10" broad. Rays 
usually none. Outer bracts of the involucre 4-6, oblong or ovate, 
very much shorter than the inner ones, which are united to the mid¬ 
dle or beyond. Disk yellow or brownish. 
On dry plains. May-August. Harmon County. 
XX. MARSHALLTA Schreb. 
Perennial, often tufted, simple or branched herbs. Leaves 
basal or alternate, entire. Heads large, long-peduncled, 
discoid, of purple, pink or white, glandular-pubescent flow¬ 
ers. Involucre broadly campanulate, bracts in 1 or 2 series, 
nearly equal. Receptacle convex, chaffy. Rays none. Flow¬ 
ers all perfect and fertile, their corollas with a deeply 5- 
lobed or 5-parted campanulate limb and a slender tube. 
Achenes turbinate, 5-ribbed and 5-angled. Pappus of 5 or 
6 acute or acuminate, ovate or lanceolate-deltoid, nearly 
entire scales. 
1. Marshallia caespitosa Nutt. Narrow-leaved Mars i-iallta. 
Stems usually tufted and simple, 8'-15' high. Leaves thick, mostly 
basal, faintly 3-nerved, linear or linear-spatulate^ Head about 1' 
broad, borne on a peduncle often 10' long. Corollas pale rose or 
white. Bracts of the involucre linear-lanceolate. 
Prairie and hills. May-June. Infrequent. 
XXI. HYMENOPAPPUS L'Her. 
Perennial or biennial, erect herbs, with angled stems. 
Leaves alternate or basal, mostly pinnatifid or dissected. 
Heads discoid, corymbose or solitary, of white or yellow 
flowers. Involucre hemispheric, bracts 6-12 in 1 or 2 series, 
mostly appressed, colored, petal-like. Receptacle small, 
