COMPOSITAE (COMPOSITE FAMILY) 521 



Biennial, erect, 2-4 dm. high, fastigiately or more corymbosely branching, 

 the herbage canescently puberulent: early cauline leaves (fallen before the 

 flowering) spatulate, commonly with a few serrations; those of the branches 

 linear or at least narrowly oblanceolate, entire: bracts of the involucre in 

 about 3 series, the lanceolate green tips ascending or slightly spreading: 

 rays rather deep blue or purplish. From Assiniboia and the Dakotas to 

 Colorado. 



11. Machaeranthera shastensis Gray, Proc. Am. Acad. 6: 539. 1865. 

 Stems several from the crown of the biennial or perennial root, paniculately 

 branched, canescently puberulent as are also the leaves, somewhat purplish: 

 leaves mostly entire, 2-4 cm. long; the lower spatulate or oblanceolate as are 

 the narrower stem leaves: heads rather numerous; the involucre subturbinate 

 to campanulate, 12 mm. high; the bracts rather thin, purplish and canescent, 

 mostly erect: rays few (8-16), rather broad, blue varying to purple. (M: 

 linearis Rydb. Mem.-N. Y. Bot. Card. 1: 398. 1900; M. superba A. Nels. 

 Bot. Gaz. 30: 197. 1900.) Northwestern Wyoming to California and Wash- 

 ington. 



12. Machaeranthera pulverulenta (Nutt.) Greene, 1. c. 23. Biennial, 

 erect, 1-3 dm. high, somewhat fastigiately panicled, more or less canescent 

 with a fine pubescence, this on the peduncular branchlets and involucres 

 mixed with sessile or subsessile very minute resiniferous glands: rather small 

 and scattered, leaves oblanceolate, entire or serrate-toothed: heads small, 

 subturbinate; involucral bracts in about 3 series, rigid, the short green tips 

 suberect: rays few (8-16). (M. divaricata and M. subalpina Greene, 1. c.) 

 Northern Colorado to Montana. 



13. Machaeranthera ramosa A. Nels. Bull. Torr. Bot. Club 28: 233. 1901. 

 Stems several to numerous, prostrate-spreading^ or somewhat assurgent, 

 each freely branched (often intricately so) throughout, 3-4 dm. long, the 

 whole plant forming a conspicuous mat from 0.5 m. to nearly 1 m. across; 

 stems and slender branchlets green with a fine puberulence: leaves green, 

 nearly glabrous; the radical and cauline entire or irregularly denticulate, 

 broadly linear or linear-spat ulate, 3-5 cm. long, often wanting at anthesis; 

 the rameal numerous, small, linear, entire or nearly so, often somewhat 

 fascicled: heads numerous, terminating the branchlets; involucres broad, 

 subhemispherical; the lanceolate bracts in 5 or 6 series and rather loosely 

 imbricated, the green, acuminate tips at length reflexed, distinctly glandular- 

 viscid: rays 20 (more or less), purple. Sandy gravelly plains; southern 

 Wyoming. 



14. Machaeranthera glabella Greene, Rydb. in Fl. Col. 358. 1906. Nearly 

 or quite glabrous throughout, 2-3 dm. high; stems few to several from the 

 somewhat branched crown of the taproot, mostly erect, simple below: leaves 

 linear to narrowly oblanceolate, somewhat rosulate on the crowns, 2-4 cm. 

 long: heads rather small, in an open corymbose panicle; involucres campanulo- 

 turbinate; the bracts pale except the short-lanceolate dark green tips, erect 

 or some of them tardily recurved: rays 10-15, 10-12 mm. long. Mountains 

 of Colorado. 



24. OREASTRUM Greene 



Acaulescent perennials, with narrow subcoriaceous entire leaves and scap- 

 iform monocephalous branches from a stout somewhat fusiform and not 

 freely branching taproot. Bracts of the involucre narrow, subequal, in about 

 2 series. Rays rather numerous, elongated, purple; disk-corollas tubular- 

 funnelform, 5-toothed and the teeth erect. Style-branches filiform to subulate- 

 linear, strongly hirsutulous. Achenes subterete, distinctly 5-8-cpstate. Pappus 

 a single series of brownish barbellate-scabrous and rather fragile or deciduous 

 bristles. 



1. Oreastrum alpigineum (T. & G.) Greene, Pitt. 3: 147. 1896. Scapiform 

 stems spreading and assurgent, 6-12 cm. long, tomentose at the summit: 

 radical leaves lingulate-spatulate to narrowly linear, glabrous, obtuse, nerve- 



