Dichastophora. COMPOSITE. 165 



K. effdsa, Gray. Perennial, often 2 feet high, with simple stem branching above into an 

 effuse ample panicle : leaves (an inch or less long) hispid as well as the stem, rigid and sca- 

 brous, oblong, mostly with a broad sessile base : heads very numerous : involucre more 

 turbinate: rays 4 to 7, white: disk-flowers somewhat more numerous, apparently always 

 sterile, and with elongated linear-lanceolate style-appendages : fertile akenes obovate, flat, 

 callous-nerved at the margins (or with one margin 2-nerved). — PI. Lindh. ii. 221; PI. 

 Wright, i. 93. — Hillsides, central parts of Texas, Berlandier, Lindheimer. 



'39. CH.ETOPAPPA, DC. (X<uV>?, bristle, and mfcraw, pappus.) — Low 

 and small Texano-Mexican winter annuals, diffusely branched ; the branches 

 terminated by small heads : rays white or purple : leaves entire, the lower spatu- 

 late, upper gradually becoming linear or reduced to subulate bracts. Fl. spring 

 and early summer. — Chcetanthera, Nutt. Jour. Acad. Philad. vii. 111. Ghm- 

 tophora, Nutt. in DC. Chcetopappa & Distasis, DC. Prodr. v. 301, 279 ; Benth. 

 & Hook. Gen. ii. 268. Diplostelma, Gray, PI. Fendl. 72. 



C asteroid.es, DC. 1. c. Slender, 2 to 10 inches high, pubescent: involucre (2 lines long) 

 rather narrow, of 12 to 14 bracts : rays 5 to 12 : disk-flowers 8 to 12 : style-appendages very 

 obtuse : akenes slender, little compressed, obscurely few-nerved, pubescent, all the central 

 ones sterile and often awnless : palese of the pappus very thin and hyaline, narrowly oblong, 

 not rarely lacerate or cleft. — Torr. & Gray, PI. ii. 187. Chcetanthera asteroides, Nutt. 1. c. — 

 Dry ground, Texas to Arkansas and the borders of Missouri. (Adjacent Mex.) 



Var. imberbis, Gray. Awns of the pappus wanting in all the flowers : the palese 

 rather broader and sometimes coronif orm-concreted. — Proc. Am. Acad. xvi. 82. — E. Texas, 

 Wright. 



C. Parryi, Gray. More rigid, 9 inches or more high : leaves subcoriaceous, hispidulous 

 and glabrate : involucre (3 lines long) turbinate : rays 6 or 7 : style-appendages short and 

 very obtuse : akenes quite glabrous ; the fertile ones fusiform and somewhat compressed, 

 4-nerved, with a pappus of 4 or 5 firmer and cuneiform-quadrate paleaj which are laciniately 

 fimbriate at the truncate apex, and of few or sometimes solitary more delicate awns, these 

 occasionally little longer than the paleae, sometimes wanting ; disk-akenes mostly inane and 

 awnless. — Proc. Am. Acad. xvi. 82. Distasis modesta, var., Gray, Bot. Mex. Bound. 78. — 

 Mt. Carmel, on the Rio Grande, between Texas and Mexico, Parry. 



C. modesta, Gray, 1. c. Less slender and pubescence more hirsute than in C. asteroides : 

 involucre broadly campanulate ; its bracts obtuser and more numerous : rays 9 to 20 : disk- 

 flowers 40 to 60, all but the central fertile ; their style-appendages narrower and acutish : 

 akenes oblong or linear, much compressed, pubescent when young, with merely marginal 

 nerves or occasionally a facial one, only the central ones sterile : pappus of 5 oblong erose- 

 truncate at length subcoriaceous palese, alternating with as many rather rigid awns. — Dis- 

 tasis modesta, DC. Prodr. v. 279. Diplostelma bellioides, Gray, PI. Fendl. 73. — Dry ground, 

 Texas, Berlandier, Wright, &c. (Adjacent Mex.) 

 Df stasis? heterofhyxla, Hemsl. Biol. Centr.-Am. Bot. ii. 119, of Mexico, is hardly of 



this genus, probably not of the tribe. 



40. MONOPTILON, Torr. & Gray. (MoVos, single, wriXov, feather, al- 

 luding to the solitary plumose bristle of the pappus.) — Jour. Bost. Nat. Hist. Soc. 

 v. 106, t. 13 ; Benth. & Hook. Gen. ii. 307 ; Gray, Bot. Calif, i. 306. — Single 

 species. 



M. bellidif orme, Torr. & Gbay, 1. c. A small but pretty annual, much branched from 

 the very base, depressed, villous-hirsute : heads terminating the numerous leafy branchlets, 

 half-iinch in diameter, inclusive of the white or violet-purple rays : leaves small, spatulate or 

 linear-spatulate, the uppermost involucrate around the head. — Arid or desert plains, S. E. 

 California to S. W. Utah, Fremont, Parry, Palmer, Parish. 



41. DICHJETOPHORA, Gray. (Ais, x a ^ # P<*> bearing two bristles, 

 i. e. pappus-awns.) — PI. Fendl. 73. — Single species ; in Benth. & Hook. Gen. 



