322 



COMPOSITE. Aster. 



§ 1. Biennials, rarely anjiuals or perennials, tvith leaves disposed to he incised or pin- 

 natifid : scales of the involucre with green tips : rays sometimes sterile : akenes 

 with strong mar; 1 1 Hul ribs and some slender nerves on both faces. {Involucre 

 commonly resi:mhlni<:i that of Corethrogyne.) — Mach^ranthera. {Machx- 

 ranthera, Nees. JJldcria, JS'utt.) 



* Hays sfyliferous, but sometimes infertile. 



1. A. tanacetifolius, HBK. Biennial or annual, pubescent and somewhat 

 viscid, a foot or k'ss hi-ii : leaves once to thiice pinnatifid, the lobes small and nar- 

 row : 'heads lar-v. loosi'ly corymbose: scales of the hemispherical involucre linear 

 and Avith spreadin.u hnliaceous tips: rays 20 or more, violet: akenes villous. — 

 Machwranthera t<unirdifolia, Nees ; Hook. Bot. Mag. t. 4624. Dieteria coronopi- 

 folia, I^utt. in Trans. Am. Phd. Soc. n. ser. vii. 301. 



S. E. California, on the east side of Providence Mountains, Dr. Cooper ; thence throngh Ari- 

 zona to Colorado, east of the Eoeky Mountains, and into Mexico. 



A. (Mach.erantheiia) pauviflora. Gray, which occurs on the Gila in Arizona, and may he 

 found within the State, is smoother and much smaller. 



2. A. incanus, Gray. Hoary with a fine and close soft pubescence, slightly if 

 at all viscid, a foot or two high, loosely branched : leaves linear or narrowly lanceo- 

 late, entire, or some with a few lateral teeth, acute (an inch or so in length, about 

 2 lines wide) : heads solitary termi-nating the branches, large : scales of the hemi- 

 spherical involucre linear-lanceolate, with long and squarrose-spreading or reflexed 

 foliaceous tips : rays 30 or more, violet : akenes canescent. — Diplopapjms in- 

 canus, Lindl. Bot. Reg. t. 1G93 ; Hook. Bot. Mag. t. 3382. Dieteria incana, Torr. 

 & Gray, Fl. ii. 100. " 



California, raised in England from seed collected by Douglas ; the station unknown. Speci- 

 mens which accord with it were gathered in Guadalupe Canon, Sonora, by Capt. E. K. Smith. 

 Head over half an inch in diameter across the disk : rays two thirds of an inch long. 



3. A. canescens, Pursh. Biennial, minutely puberident-hoary or often green, 

 a foot or so in height : stems rigid, corymbosely or paniculately branched above : 

 leaves varying from oblong-lanceolate or the lowest spatulate to linear, incisely or 

 almost spinufosely toothed, or sometimes entire, those of the flowering branches 

 reduced to subulate bracts : heads few or numerous, solitary, or mostly corymbose 

 or panicled : scales of the campanulate or obconical involucre rigid, appressed, 

 with short more or less squarrose-spreading green tips, the outer successively 

 shorter : rays 20 to 30, violet or bluish-purple : akenes canescently-pubescent. — 

 A biennis, Kutt. Gen. ii. 155. Dieteria canescens, jndverulenta, divaricata, viscosa, 

 &' sessiliflora, Nutt. in Trans. Am. Phil. Soc. 1. c. Macharanthera canescens, Gray, 

 1, c. ; Eaton in Bot. King. 



Dry recrions, in the mountains behind San Diego and on the eastern slope of the Sierra Kevada 

 (Mono an^l Tahoe Lakes, &c.), extending north to the British boundary, and east to the eastern 

 base of the Eoeky ]\Iountains : a characteristic and most variable species ot _ the region. Heads 

 in the larger forins half an inch in diameter, and the rays half an inch long ; m others barely halt 

 that size, and the flowers much fewer. It is useless to distinguish particular varieties. Only low 

 and small-headed forms have as yet been found in California. 



ft ft Bays completely neutral. — Hesperastrum, Gray. 



4. A. ShastensiS, Gray. Dwarf from a perennial rootstock, branched and 

 tufted from the base, a spaii high, puberulent-hoary : leaves small, spatulate or ob- 

 long, entire : heads solitary terminating the branches, small : scales of the campanu- 

 late' involucre lanceolate, someAvhat hoary and viscid, the outer with loose green 

 tips, the inner nearly destitute of herbaceous tips : rays 15 to 20, rose-violet. — 

 Maclia'ranthera {Hesjierastrum) Shastensis, Gray, Proc. Am. Acad. vi. 539. 



On Mount Shasta, at about 9,000 feet, Brewer. Resembles a dwarf state of the last. Involu- 

 cre 4 lines long : rays 3 lines. 



