284 COMPOSITJE. Helianthella. 



or cuneate and acute : mature akene 5 lines long. — Tithonia argopliylla, Eaton, Bot. King 

 Exp. 423. Encelid (Geraa) argophyUa, Gray, 1. c. — S. W. Utah, near St. George, Palmer. 

 Incompletely known. Perhaps the two are not specifically different. 



§ 2. Helianthella proper. Habit somewhat of Wyethia, leafy-stemmed: 

 leaves from lanceolate to ovate, mostly triplinerved above the tapering base, and 

 commonly venulose-i'eticulated, varying from opjaosite to alternate : rays broad : 

 tube of the disk-corollas usually nearly half the length of the throat, and the 

 short ovate lobes more or less puberulent : akenes flat, from cuneate-obovate and 

 emarginate to slightly obcordate : style-appendages obtuse, mostly short and spat- 

 ulate or oblong. 



# Chaffy bracts of the receptacle soft and scarious : akenes with some long villous hairs on the 

 margins and sometimes on the faces. 



H— Heads showy, large or middle-sized, .solitary, or some later ones in the axils of bract-like 

 leaves below: bracts of the involucre loose and lanceolate-attenuate or linear, more or less 

 foliaceous, conspicuousl}' hirsute-ciliate : disk yellowish, with dark anthers. 



H. quinquenervis, Gkat. Somewhat hirsutely pubescent or almost glabrous : stems 

 solitary or scattered, 2 to 4 feet high ; leaves mostly opposite, oblong- or ovate-lanceolate, 

 acuminate, 4 to 9 inches long, triplinerved below the middle and commonly with a lower 

 pair at some distance, uppermost sessile, lower ones tapering into margined petioles, and the 

 lowest (a foot or more long) into longer petioles : head mostly long-ped uncled, ample, the 

 disk a full inch in diameter: bracts of the involucre lanceolate, more or less foliaceous: 

 rays 15 to 20, pale yellow, commonly inch and a half long: akenes cuneate-obovate and 

 obscurely obcordate, 4 lines long, with margins and commonly a part of the faces long- 

 villous : pappus of 2 slender awns, of half the length of the akene, and nearly thrice the 

 length of the squamellse, which form a conspicuous finely dissected fringe. — Proc. Am. 

 Acad. xix. 10. Helianthus quiiiquenerris, Hook. Lond. Jour. Bot. vi. 247. Helianthella 

 unlflora. Gray in Proc. Acad. Philad. 1863, 65; Porter & Coulter, El. Colorado, 71 ; Eaton 

 in Bot. King Exp. 170; not Torr. & Gray, El., except as to one of Nuttall's specimens of 

 Leighia uniflora, but not the original from Wyeth. — Rocky Mountains from Dakota and 

 Montana to S. Colorado. 



Var. Arizonica. Akenes obovate, even 5 lines long, with delicate awns rarely twice 

 the length of the broader squamella;. — Xortheru Arizona, Woodhouse, and S. W. Arizona, 

 Lemmon, 

 -H. Parryi, Gray. Hispidulous-hirsute : stems numerous from a thickened root, a foot high, 

 rather slender : leaves mostly alternate, more rigid, lanceolate and an inch or two long, or 

 the lowest and radical oblong-spatulate and of double the size : heads and rays barelv half 

 the size of the preceding : pappus of fimbriately dissected squamellse only, or with a pair 

 of slender awns not surpassing these. —Proc. Acad. Philad. 1863, 68; Porter & Coult. El. 

 Colorado, 71. — Rocky Mountains of Colorado and northern part of Kew Mexico, at 8,000 

 to 10,000 feet. Parry, Hall, &c. 



H. MexicAna, Gray, Proc. Am. Acad. xi. 37, of San Luis Potosi, Mexico, ranks between 

 the preceding and the following, but is nearer the former; has solitary heads, dark brownisli 

 disk of 4 lines in diameter, broad rays half-inch long, and almost linear "leaves. 



^- -I- Heads small: involucre more imbricated : rays few and hardly surpassing the dark-purple 

 disk. 



H. miorocephala, Gray. Hispidulous-scabrous : stems numerous from a greatly thick- 

 ened root, a foot or less high, slender, somewhat paniculately or coryii\l)oselv branched at 

 summit and bearing several heads: leaves ri^id, all but the lou-er alternate ; radical lanceo- 

 late-spatulate ; upper cauline nearly linear and sessile, inch long: iuvohure somewhat cam- 

 panulate, 3 or 4 lines high ; its bracts linear-oblong, mostly obtuse : rays not over 3 lines 

 long : immature akenes villous, at loa.st at the summit : piijipus of sever:il' slender squamella; 

 intermixed with the long hairs, longer than the breadth of tlto ovarv, two marginal ones 

 often e.xtended and awn-like. — Proc. Am. Acad. xix. 10. Encelia (Geraa) microrephala. 

 Gray, Proc. Am. Acad. viii. 657. — Borders of CVdorado and adjacent New Mexico and 

 Utah, north to Rabbit Valley, Newberry, Braml,;/ce, Ward. 



