COMPPSITAE (composite FAMILY) 499 



1-2.5 cm. long, firm, spinulose-dentate: heads terminating the stem or 

 branches; /involucre carapanulate, the bracts linear, acute, pnberulent, the 

 tips somewhat spreading, the outer shorter than the inner: achenes densely 

 silky-tomentose. Aplopappus NvUallii. — Pry soil; from New Mexico and 

 Arizona to, the Canadian border. , 



4. Sideranthus austraU? (Greene) Rydb. Bull. Torr. Bot. Club 27: 621. 

 1900. Perennial, the clustered stems, erect or ascending, 1-4 dm. high, not 

 tomentose but cinereous with a short spreading somewhat glandular indu- 

 ment: radical leaves pinnatifid, the lobes with few cparse teeth; the cauline nar- 

 row, pinnately toothed: he^idafew, solitary at the ends of leafy pedunculiform 

 branches; rays pale yellow: aphenes compressed; pappus-bristles not coarse, 

 extremely unequal. (<S. pubendus Rydb. 1. c. In this and the next species 

 there are all degrees of pubescence.)-— Colorado and New Mexico. 



5. Sideranthus spijnulosus (Pursh) Sweet. Hort. Brit. 227. 1826. From 

 lanate or tomentose to glabrate, much branched at the base, perennial from 

 thick woody roots, 1-4. dm. high: leaves pinnatifid, Unear to ovate in outline, 

 1-3.5 cm. 'long, the lobes with bristle-pointed teeth: heads several or nu- 

 merous, 12-25 mm. bi'oad; involucre hemispheric, the bracts linear, acute, 

 appressed: achenes pubescen|;, narrowed below; pappus soft and capillary. — 

 On the plains; from the base of the,moimtains to th«! Dakotas, Nebraska, and 

 Texas.. 



5a. Sideranthus spinulosus glaberrimus (Rydb.) A. Nels. Wholly gla- 

 brous; not otherwise distinguishable. (<S. gla^errirmts Rydb. 1. c.)— Same 

 range as the species. 



12. PYRROCOMA Nutt. 



Perennial herbs with mostly simple stems, alternate leaves, and showy 

 heads of yellow flowers terminal or in th^ axils of the upper leayeS. Heads 

 many-flowered, radiate. Bracts of the hemispherical or campanulate in- 

 volucre rigid, somewhat foliaceous, nerveless, oblong with more or less squar- 

 rose or herbaceous tips. Receptacle flat, alveolate-toothed. Ray-flowers 

 numerous, pistillate; disk-flowers cyUndrical, slightly dilated upward with 

 short, erect teeth. Style-branches of the disk-flowers subulate-linear, elon- 

 gated, the hispid appendages much longer than the stigmatio portion. Achenes 

 linear, elongatedi,. somewhat 3-angled and striate, glabrous or rarely hairy. 

 Pappus reddish-brown or: fulvous, of copious and uniform, slender, rigid 

 bristles. — Aplopappus in part. 



Iixvolucral bracts with broad obtuse tips 1. P. crocea. 



Involucrai braets acute or acuminate. 



Heads mostly solitary, terminal, rarely 1-2 smaller ones in the upper 

 axils. 

 Heads large, the disk more than 2 cm.. in diameter. . 



Stem and involucre villous . 2. P. Clementis. 



Stem and' involucre glabrate . . .. , . 4 . 3. P. integrifolia. 

 Heads smaller;' the disk less than 2 cm. in diameter . . .4. P. uniflora. 

 Heads several to many, paniculately corymbose or j'acemiform . 5. P. lanceolata. 



1. Pyrrocoma crocea (Gray) Greene, Erythea 2: 69. 1894. Stems stout 

 and erect, commonly 3-5' dm. high, and with radical leaves (including the 

 petiole) 1-2 dm.i long: cauline leaves ovate-oblong to lanceolate,, partly clasp- 

 ing: heads mostly solitary; involucre about 3 cm. in diameter; the bracts ovate 

 to spatiilate-oblong, very obtuse, lax, inner with scairious, erose-denticulate 

 margins: rays saffron-yellow, sometimes 25 mm. long: achenes narrowly ob- 

 long, nearly as. long as the, pappus. Aplopappus crocea. — In the Colorado 

 mountains. 



2. PyirocpmaClementisRydb. Bull. Torr. Bot. Club 27: 625. 1900. Stems 

 1 or more, ascending, 1-2 dm. high, more or less villous as is also the in- 

 volucre: lower stem leaves Hnear-oblong, about 1 dm. long, glabrous except 

 the ciliate margin, saliently dentate; the upper lanceolate or ovate-lanceolate, 

 dentate or entire-margined: heads soUtary; disk about 2.5 cm. broad; bracts 

 all foliaceous, imbricated in 3-4 series, but the outer almost equaling the 



