Diduetophora. COMPOSITE. 165 



KL. effusa, 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 akeucs obovate, flat, 

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

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



39. CH^ETOPAPPA, DC. (XCU'TT/, bristle, and TraTTTro?, 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. Chcetanlhera, Nutt. Jour. Acad: Philad. vii. 111. Chce- 

 tophora, Nutt. in DC. Ghcetopappa & Distasis, DC. Prodr. v. 301, 279 ; Beuth. 

 & Hook. Gen. ii. 2G8. 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 : akeues slender, little compressed, obscurely few-nerved, pubescent, all the central 

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

 not rarely lacerate or cleft. Torr. & (iray, Fl. ii. 187. Chceianthera asteroidcs, 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 paleas 

 rather broader and sometimes corouiform-coucreted. Proc. Am. Acad. xvi. 82. E. Texas, 

 Wright. 



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

 and giabrate : 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 aud cuneiform-imadrate pale-rc which are laciniately 

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

 occasionally little longer than the paletxi, sometimes wanting; disk-akeues mostly inane and 

 awnlcss. Proc. Am. Acad. xvi. 82. /_>/.,/, fx/.s mudesta, 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- 

 truucate at length subcoriaceous paleai, alternating with as many rather rigid awns. Dis- 

 tasis modesta, DC. Prodr. v. 279. Diphstelma bellioides, Gray, PL Feucll. 73. 1 >ry ground, 

 Texas, Berlamlin-, Wr'njht, &c. (Adjacent Mex.) 

 DfsTASis? HETEROPHYLLA, Hemsl. Biol. Ceutr.-Am. Bot. ii. 119, of Mexico, is hardly of 



this genus, probably not of the tribe. 



40. MON6PTILON, Torr. & Gray. (MoVos, single, TmXoi/, 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. 300. Single 

 species. 



M. bellidiforme, TORR. & GRAY, 1. c. A small but pretty annual, much branched from 

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

 half-inch 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. I 

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



41. DICH^ET(5PHORA, Gray. (k, x<"7, <H^ bearing two bristles, 

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



