CARDUACEAE 1205 
1. Thurovia triflóra Rose. Stems 2-4.5 dm. tall, slender, with straggling or bushy 
branches : leaves few; blades linear, 6-18 mm. long, acute, entire: involucres about 3 
mm. high, 3-flowered ; bracts few, the outer with green linear acute tips : corolla-lobes 
spreading: achenes turbinate, 1 mm. long: pappus-scales 2 mm. long, the base oblong, 
the tips slender, shorter than the bases, sometimes barbed. 
On prairies, Texas. Fall. 
46. CHAETOPAPPA DC. 
Annual or biennial very slender caulescent herbs. Leaves alternate: blades entire, 
ciliate or spinulose-serrulate. Heads small, radiate. Involucres narrow: bracts in few 
series, acute or acuminate. Receptacle flat, naked.  Ray-flowers in 1 row, pistillate. 
Disk-flowers perfect or the central staminate. Anthers obtuse and entire at the base. 
Stigmas with narrow obtuse appendages. Achenes nearly terete, 5-ribbed, sometimes nar- 
rowed at both ends. Pappus of 5 or more scales alternating with 5 scabrous bristles. 
Involucres 4 mm. high: achenes pubescent : pappus-scales narrowly oblong. 1. C. asteroides. 
Involucres 6 mm. high: achenes glabrous or nearly so; pappus-scales cuneate. 2. C. Parryi. 
1. Chaetopappa asteroides (Nutt.) DC. Stems slender, 0.5-3 dm. tall, minutely 
pubescent, more or less diffusely branched. Leaf-blades spatulate to linear, 0.5-2 cm. long, 
the lower ones slender-petioled : involucres 4 mm. high, oblong or oblong-turbinate ; bracts 
linear, glabrous, scarious-margined, spreading in age: ray-flowers 5-12; ligules narrowly 
oblong, 2-3 mm. long: achenes 1.5 mm. long: pappus-scales oblong, hyaline. 
In dry soil. Missouri to Texas. Spring and summer.— A form without pappus-awns in any flow- 
ers and the pappus-scales crown-like, is C. asteroides imbérbis A. Gray. Eastern Texas. 
2. Chaetopappa Parryi A. Gray. Stems 1-2 dm. tall, nearly glabrous, corymbose 
above, the branches wiry, leaf-blades somewhat leathery, spatulate to linear-oblanceolate. 
1-2 em. long, acutish or apiculate, ciliate : involucres cylindric, 6 mm. high ; bracts linear- 
lanceolate to linear, acute, with broad scarious margins: ray-flowers 6-7, with oblong lig- 
ules : achenes 2.5 mm. long, glabrous or nearly so: pappus-scales cuneate, 4-5. 
In dry soil Texas. Spring and summer. 
47. DISTASIS DC. 
Annual relatively low caulescent herbs, with pubescent foliage. Leaves alternate : 
blades entire or sparingly toothed. Heads small, radiate, peduncled. Involucres hemi- 
spheric or campanulate, many-flowered : bracts scarious-margined, in few series. Receptacle 
flat, slightly pitted. Ray-flowers pistillate, in about 1 series. Disk-flowers perfect, fruit- 
producing. Anthers obtuse and entire at the base. Style-branches flattened, with narrow 
appendages. Achenes flattened, with slightly margined nerves. Pappus a series of hyaline 
scales alternating with as many bristles. 
1. Distasis modésta DC. Stems commonly branched at the base, 0.5-3 dm. tall, 
hirsute and strigillose. Leaf-blades spatulate to linear, 0.5-1.5 cm. long, acute or acutish : 
involucres 3 mm. high, hemispheric ; bracts linear, acute or acuminate, often sparingly 
pubescent: achenes 2 mm. long, pubescent: pappus-scales 5, truncate or eroded at the 
apex, alternating with 5 bristles. 
In dry soil, Texas and adjacent Mexico. 
48. TOWNSENDIA Hook. 
Tufted scapose or caulescent herbs, often with caudex-like stems or branches. Leaves 
alternate: blades narrow, often crowded and broadest above the middle, entire. Heads 
relatively large, showy, sessile or peduncled. Involucres campanulate to hemispheric : 
bracts herbaceous, in several series. Receptacle nearly flat. Ray-flowers pistillate, with 
white or pink ligules. Disk-flowers mostly perfect. Anthers obtuse and entire at the base. 
Stigmas flattened, each with a lanceolate or narrow appendaged. Achenes various, those 
of the ray mostly 3-angled, those of the disk flattened. Pappus a single series of firm 
bristles or scales. 
1. Townsendia Wilcoxiàna Wood. Depressed, tufted. Leaves several or numer- 
ous, crowded on the short caudex-like stems ; blades linear-spatulate, 2-4.5 cm. long, spar- 
ingly pubescent: heads sessile: involucres about 1 cm. high; bracts lanceolate to linear- 
lanceolate, the inner 11-13 mm. long, like the outer ciliate and often magenta-tipped : ray- 
flowers numerous, with narrow ligules 1-1.5 cm. long. 
In dry soil, Colorado to the Indian Territory and Arizona. Spring and summer. 
