245 
115. CHAPTALIA Vent. 
Low floccose-tomentose chiefly stemless perennial herbs, with leaves 
in a radical tuft (persistently canescent beneath, glabrate above), naked 
elongated scapes bearing solitary radiate heads of white or purplish 
flowers (ray-flowers pistillate and fertile, simply ligulate; disk-flowers 
perfect and all or some of them sterile, more or less bilabiate), narrow 
appressed-imbricated involucral bracts (the outer successively shorter), 
naked receptacle, oblong or fusiform 5-nerved achenes attenuate or beaked 
at apex, and pappus of copious very fine and soft capillary bristles. 
1. C. tomentosa Vent. Leaves spatulate or oblanceolate, thickish, entire or 
retrorsely denticulate, white beneath with dense matted tomentum: rays broadly 
linear: achenes glabrous, merely attenuate into a neck.—Extending from the pine 
barrens of the Gulf States into eastern Texas, but with unrecorded western limit. 
2. C, nutans Hemsl. Leaves obovate or oblong, sometimes lyrate-sinuate, thin, 
white beneath with more cottony or even webby tomentum: rays small and narrow, 
little exserted: achenes pubescent or glabrate, with slender filiform beak as long as 
the body.—Wooded grounds of Texas, to Arizona and Mexico. 
116. PEREZIA Lag. 
Perennial herbs (usually a tuft of wool at base of stem), with coria- 
ceous or papery reticulated leaves, solitary or paniculate or cymose 
heads of fragrant rose-purple to white perfect and fertile scarcely 
bilabiate flowers, dry and firm involucral bracts imbricated in few to 
several series, flat mostly naked receptacle, puberulent elongated-oblong 
terete or obscurely angled achenes sometimes narrowed but not beaked, 
and pappus of copious capillary scabrous bristles (either rather rigid or 
soft). 
* Low: heads single or few, 12 to 24mm. long, 20 to 30-flowered. 
1. P. runoinata Lag. Acaulescent, scabrous-puberulent or glabrate: rootstocks 
short, sending down tuberous-thickened fascicled roots: radical leaves runcinate- 
pinnatifid, 10 to 20cm. long, thin; lobes rounded, copiously fringed with spinulose 
teeth, margined-petioled: scapes naked, equaling the leaves, bearing solitary or a 
few pedunculate heads: involucral bracts setaceous-acuminate: pappus rather sor- 
did.—Dry ground, eastern and southern Texas. 
2. P. nana Gray. Leafy-stemmed and glabrous: rootstocks slender, creeping: 
first leaves small and scale-like; principal stem-leaves firm, orbiculate, dilated-obo- 
vate, or ovate (2.5 to 5em. long), coarsely spinulose-dentate, sessile or partly clasp- 
ing: heads mostly sessile, solitary and terminal: involucral bracts acutish: pappus 
white.—Dry plains and rocky bluffs, throughout southern Texas (and adjacent 
Mexico) to Arizona. 
* * Taller (3 to 9 dm. high), branching, leafy up to the corymbose many-headed inflores- 
cence: heads 8 to 12-flowered, 12mm. or less long. 
3. P. Wrightii Gray. Mostly glabrous throughout: leaves thin, oblong to nearly 
ovate, densely spinulose-dentate, often unequally or doubly so, closely sessile by 
sagittate-cordate (or truncate) base: involucral bracts all pointless and obtuse.— 
Rocky hills and ravines, along the Pecos and westward. 
117. TRIXIS P. Browne. 
Suffruticose plants, with entire or denticulate leaves, rather few- 
flowered heads of perfect and fertile bilabiate yellow flowers, 8 to 12 
