197 
19. A. ericzfolius Rothrock, Low, strigosely canescent or hispidulous and gland- 
ular-scabrous, much branched: branches erect or diffuse, terminated by somewhat 
pedunculate smaller and narrower heads (6 to 8 mm. high): leaves commonly hispid- 
ciliate, erect or little spreading, 6 to 12 mm. long; the lowest spatulate, the upper 
from linear to nearly filiform: involucral bracts lanceolate, acute or apiculate, 
thinnish: achenes less compressed, lightly few-nerved. (Diplopappus ericoides Torr. 
& Gray.)—Dry hills, throughout Texas. Rays sometimes white. 
§6. ORTHOMERIS. Pappus simple: involucral bracts imbricated, appressed, without herba- 
ceous tips, often scarious-edged or dry.—Involucre and herba ge smooth and gla. 
brous, and plants more or less woody. 
20. A. spinosus Benth. Base of stem usually persistent and woody, sending up 
(9 to 24 dm, long) slender and lithe striate green branches, resolved into paniculate 
branchlets, terminated by small heads: stem leaves small, more or less fleshy, linear 
or spatulate-lanceolate, entire, mostly few and fugacious, some of them with soft 
subulate spines in or above their axils; those of the branchlets reduced to subulate 
scales or wanting: involucre 4mm. high, of subulate-lanceolate bracts: rays white, 
4mm. long: achenes glabrous.—Apparently very common in southwestern Texas, 
Dr. Havard speaks of it as ‘that most common of bushy weeds,” 
21, A. Palmeri Gray. Decidedly shrubby, 9 to 12 dm. high, very much branched 
throughout: branchlets slender, striate-angled, terminated by the small heads: 
leaves apparently not fleshy, narrowly linear, entire: involucre barely 6 mm. high, 
of narrowly oblong obtuse bracts: rays white, 2 mm. long: achenes sericeous-pubes- 
cent,—About Corpus Christi Bay; also reported from Eagle Pass on the Rio Grande. 
§7. OXYTRIPOLIUM. Involucre asin §6: pappus simple, fine and soft: glabrous annuals, 
bearing numerous small heads and narrow entire leaves. 
22. A. exilis Ell. Mostly slender and diffusely branched above: principal stem 
leaves linear, 7.5 to 10 cm. long, 2 to 4 mm. wide; the lowest sometimes broader and 
lanceolate, rarely with a few serratures: heads 6 mm. high: involucral bracts 
linear-subulate or more lanceolate and acuminate: ‘ays bluish or purple, rather con- 
spicuous.—Throughout Texas in subsaline or moist soil. 
§8. MACHARANTHERA. Involucre imbricated in many rows, the bracts linear, coriaceous 
below, with foliaceous spreading lips rays numerous and conspicuous, violet or 
bluish-purple: pappus copious and simple, of rather rigid and unequal bristles. In 
ours the involuere is from nearly glabrous to canescent, and the achenes densely 
pubescent. 
* Leaves at most incisely dentate. 
23. A. gymnocephalus Gray. Stem erect, simple or branched, commonly hirsute 
or hispidulous, equally leafy to the top: branches bearing solitary usually naked- 
pedunculate heads: leaves spatulate-oblong to lanceolate; canline short, usually 
obtuse, copiously serrate or denticulate with spinulose-setigerous teeth: involucral 
bracts linear-subulate with squarrose tips: rays purple.—Dry ground, extreme south- 
western Texas. 
24, A.canescens Pursh. Commonly 3 to 6 dm. high and loosely much branched, 
bearing numerous paniculate heads, sometimes dwarf and with simple contracted 
inflorescence, pale and cinereous-puberulent or minutely canescent, or greener and 
glabrate: leaves lanceolate to linear or the lower spatulate, from entire to irregularly 
dentate, or occasionally laciuiate, the rigid teeth mostly with mucronate-setulose tip : 
heads from 8 to 12mm. high: involucral bracts with the green tips short and spread- 
ing: rays violet. (Macharanthera canescens Gray.)—Open and sterile ground and 
sandy stream-banks, extending from the northern Great Plains to W. Texas. Anex- 
ceedingly variable species. A common western Texan variety is var. VIRIDIS Gray, a 
green hardly rigid form, of less arid situations, either sparsely scabro-puberulent or 
almost glabrous, with looser involucral bracts, either with short and ascending or 
longer and squarrose-spreading tips. (M. canescens, var, glabra Gray.) 
