Aster. COMPOSITE. 173 



compressed, mostly flat and with callous marginal nerves only : pappus simple, 

 or with an indistinct short outer series. — Gray, Proc. Am. Acad. xvi. 97. Con- 

 sists of A. Ainellus and the following, of less marked character. 



A. alpinus, L. A span or more high, witli simple erect stems from a thickish caudex, bear- 

 ing a single large head, cinereous-pubescent : leaves entire, somewhat 3-uerved, spatulate ; 

 upper small and linear : iuvolucral bracts loosely erect, oblong-linear, herl)aceous, all nearly 

 equalling tlie disk : rays violet : akenes hirsute : usually a manifest sliort outer pappus. — 

 Spec. ii. 872; Jacq. Fl. Austr. t. 88; Bot. Mag. t. 199; Hook. Fl. ii. 6. — Arctic shores, 

 Pelly. Alpine region of northern Rocky Mountains, down to about lat. 49°, Drummond, 

 Burke, Boitnjcau, Mucoun. The American plant mostly with fewer and shorter rays. (Eu., 

 N. Asia.) 



§ 2. MegalXstrum. Head very large (an inch in diameter exclusive of the 

 large and numerous rays, pedunculate and solitary, terminating rigid branches) : 

 bracts of the hemispherical involucre imbricated in 2 or 3 unequal series, some- 

 what herbaceous, gradually attenuate-acuminate : akenes oblong, compressed, 

 2-4-nerved : pappus-bristles unusually coarse and rigid, rather scanty. — Gray, 

 PL Wright, ii. 7o. (Related to subsection Xylorrhiza and to Townsendia.) 



A. "Wrightii, Gray, 1. c. Viscous-pubescent, a foot or more high : leaves oblong-spatulate, 

 setiferous-niucronate, entire, or with one or two setiferous teeth, an inch and a half long 

 including the margined petiole, thickish, obscurely veined : bracts of the involucre ovate- 

 lanceolate or the inner narrower, rather lax, viscid, slightly scarious-margined, the caudate- 

 acuminate tips surpassing the disk: rays purple, narrowly oblong, 30 to 40 (8 or 9 lines 

 long): akenes (young) loosely pubescent: pappus white, of unequal strongly denticulate 

 bristles, the larger almo.st aristiform. — Townscndia {Metjitlastrum) Wn'</lifll, Gray, Bot. 

 Mex. Bound. 78. — Eocks and stony hills on the Rio Grande, S. W. Texas, from the mouth 

 of the gi'eat canon, Wrigid, Bifjeloir. 



A. tortifolius, Gray. Tomentose-pubescent, at length glabrate, 2 feet high : leaves from 

 oljlong to narrowly lanceolate, rigid, spinulosely dentate and acuminate, sometimes incisely 

 pinnatitid, veiny : involucral bracts narrower and more numerous, lanceolate-subulate, rigid, 

 the longest barely equalling the disk : rays pale purple or violet, often an inch long : akenes 

 sericeous-canescent : ])appus at length ferruginous, deciduous in a ring. — Broc. Am. Acad. 

 vii. 353, & Bot. Calif, i. 323, not Michx. Aplopappns tortifolius, Torr. & Gray, Jour. Bost. 

 Soc. Nat. Hist. V. 109. — Mountains bordering the Mohave Desert, S. E. California to S. 

 Utah, Fremont, Newberry, Cooper, &c. 



§ 3. IlELEisTEUM. Heads mostly smaller : pappus (simple) unusually coarse 

 and rigid, the stronger bristles somewhat clavellate at tip : bracts of the involucre 

 partly or the outer wholly foliaceous and linear-lanceolate, rigid, imbricated in 

 several series, but the outermost little shorter than the inner : receptacle alveo- 

 late or fimbrillate : style-appendages filiform-subulate : akenes narrow and mostly 

 slender, little compressed, 8-10-nerved, nearly glabrous: leaves all linear and 

 entire or with some spinulose teeth, rigid, one-nerved and with obscure lateral 

 nerves : rays numerous and elongated : pappus ferruginous or tawny. — Gray, 

 Proc. Am. Acad. xvi. 97. Heleastrum, DC. Prodr. v. 263. 



* Leaves as if gramineous, and bearing some spinnliform serratures or dentictdations, mostly cus- 

 pidate at tip, smooth and glaljrous; stems simple from a tuberiform rootstock, strict and slender, 

 rigid, 2 feet high, pilose below, or the base of the leaves ciliate with some long and jointed hairs: 

 flowering in summer. 



A. eryngiifolius, Torr. & Gray. Stems hearing solitary or 2 or 3 large heads : leaves 

 mostly lanceolate-linear (2 or 3 lines wide, the larger 4 inches long, upper ones gradually 

 reduced to erect bracts) : involucre hemispherical, very many-flowered ; its bracts liuear- 

 lauceolate, attenuate into an almost setiform cusp : rays an inch long, pale blue or white. — 



