CARDUACEAE 1203 
41. APHANOSTEPHUS DC. 
Annual or biennial, or probably perennial caulescent herbs, with pubescent foliage. 
Leaves alternate: blades entire, toothed or pinnately lobed. Heads radiate. Involucres 
many-flowered, hemispheric: bracts narrow, in few series, scarious-margined. Receptacle 
convex or conic. Ray-flowers pistillate, with white violet or purple ligules. Disk-flowers 
perfect, yellow. Anthers obtuse at the base. Stigmas with obtuse appendages, Achenes 
many-ribbed. Pappus an entire toothed or ciliate crown. 
Pappus a toothed or laciniate crown: base of the corolla-tube hard and thick. 1. A. skirrobasis. 
Pappus a short ciliate crown: base of the corolla-tube barely thickened. 
Stems softly pubescent: inner achenes prominently ribbed. 2. A. humilis. 
Stems hispidulous : inner achenes obscurely if at all ribbed. 3. A. ramosissimus. 
1. Aphanostephus skirróbasis ( DC.) Trelease. Foliagecinereous-pubescent. Stems 
more or less diffusely branched at the base, 1-4 dm. long : leaf-blades spatulate, oblong or 
linear, 1.5-6 em. long, the lower ones sharply toothed or ineised, the upper entire: heads 
showy, long-peduncled : involucres 5-6 mm. high, hemispheric ; bracts linear or narrowly 
linear-lanceolate, the outer ones minutely pubescent: ray-flowers many ; ligules linear: 
achenes pubescent with a pappus of several lobes or teeth. 
On plains, Kansas to Texas and in Florida. Spring and summer. 
2. Aphanostephus hümilis (Benth.) A. Gray. Foliage softly pubescent. Stems 
branched at the base ; branches 1-3 dm. long, often decumbent : leaf-blades pinnatifid, or 
entire above, 1-6 cm. long: | heads slender-peduncled : involucres hemispheric, 3-4 mm. 
high ; bracts linear, acute, ribbed, minutely pubescent : ligules of the ray-flowers 4-8 mm. 
long, linear-oblanceolate. 
In dry ground, Texas and adjacent Mexico. 
3. Aphanostephus ramosíssimus DC. Foliage hispidulous. Stems often diffusely 
branched at maturity, 1-3 dm. long; leaf-blades various, those of the basal or lower stem- 
leaves 5-10 cm. long, spatulate, pinnatifid or incised ; those of the upper leaves linear, 
mostly entire, sessile: heads long-peduncled: involucres hemispheric, 4-5 mm. high; 
bracts linear or narrowly linear-lanceolate, the outer often pubescent: ligules of the ray- 
flowers 6-10 mm. long, linear-spatulate. 
On sandy or rocky prairies, Texas and adjacent Mexico. 
42. DICHAETÓPHORA A. Gray. 
Annual relatively low caulescent or scapose herbs. Leaves alternate, sometimes mainly 
basal: blades broadened upward, entire. Heads radiate, sometimes solitary. Involucres 
many-flowered: bracts in about 1 series. Receptacle a little convex, pitted. Ray-flowers 
numerous, pistillate, fruit producing, with white or pink ligules. Disk-flowers perfect. 
Anthers entire and obtuse at the base. Stigmas flattened, with triangular-lanceolate ap- 
pendages. Achenes flattened, broadened upward, pubescent. Pappus of 2 spreading awns 
and several minute scales, usually hidden by the pubescence of the achene. 
1. Dichaetophora campéstris (T. & G.) A. Gray. Plant finely hirsute, at first 
acaulescent, with a single scape, later somewhat branched, each branch terminating in a 
peduncle 3-6 cm. long which bears a single head : leaf-blades spatulate to oblong-spatu- 
late, 1-3 em. long, entire: involucre 3-4 mm. high; bracts linear, slightly acuminate, 
sparingly pubescent : ray-flowers 10-20, with white or pink ligules 5-8 mm. long : achenes 
cuneate, 1.5 mm. long, margined, ciliate. 
In dry soil, southern Texas and adjacent Mexico. Spring to fall. 
43. BOLTONIA L'Her. 
Perennial large caulescent herbs, with glabrous foliage. Leaves alternate: blades 
narrow, entire, sessile and sometimes decurrent. Heads often numerous, radiate. In- 
volucres broadly campanulate or hemispheric, many-flowered : bracts in few series. Re- 
ceptacle convex or conic, pitted. Ray-flowers often numerous, pistillate. Disk-flowers 
perfect. Anthers obtuse and entire at the base. Stigmas flattened, with relatively short 
appendages. Achenes flattened, broadest above the middle, with winged or thickened 
margins. Pappus a series of short scales, usually accompanied by 2—4 slender bristles. 
Disk about 4 mm. broad at maturity. 1. B. diffusa. 
Disk 6-12 mm. broad at maturity. 
a. Leaf-blades merely sessile. 
