STANDLEY FLORA OF GLACIER PARK. 419 



covering of soft hairs reminding one of fur. In some of the Glacier Park specimens 

 the heads are not very hairy, and these collections might be referred to H. griseum 

 Rydb., which, however, is probably only a form of H. scouleri. 



6. Hieracium gracile Hook. Alpine hawkweed. Frequent above or near timljer 

 line, on rocky slopes and in meadows. Alaska to Calif., N. Mex., and Alta. — Stems 

 usually 10 to 20 cm. high, short-hairy; leaves oblanceolate, 3 to 6 cm. long, long- 

 stalked, entire or with few low teeth; heads usually few, 8 to 10 mm. high; flowers 

 pale yellow. 



Very luxuriant plants collected at Granite Park are nearly 40 cm. high and have 

 numerous heads, the lower ones on very long slender stalks. 



8. PEENANTHES Vaill. 



1. Prenanthes sagittata (A. Gray) A. Nels. Rattlesnake-root. Frequent at 

 low and middle altitudes, usually in wet woods or thickets, frequently in swamps. 

 Mont, and Idaho. {Nabalus saqittatus Rydb.) — Perennial, glabrous, 30 to 60 cm. high, 

 with very leafy stems; leaves triangular or arrow-shaped, thin, toothed, stalked; 

 heads about 12 mm. high, narrow, in a narrow panicle; flowers pure white; pappus 

 of brownish bristles. 



The flowers are rather handsome, but not very showy; they open late in the season. 



86. ASTERACEAE. Aster Family. 



Herbs or rarely shrubs; leaves alternate or opposite, simple or compound; flowers 

 in heads, clustered on a receptacle, the head surrounded by an involucre of bracts; 

 disk Jloivers (the inner flowers of the head) with a small tubular 5-lobed corolla; outer 

 flowers of the head often with a narrow strap-shaped corolla {ray); fruit an achene, 

 usually bearing at the summit pappus, this representing the calyx and composed of 

 scales, bristles, or awns. — The largest family of plants. The name Compositae is 

 frequently applied to this and the Cichoriaceae, which are often united as a single 

 family. 

 A. Flower heads without rays. 



Leaves with spine-tipped teeth 27. CERSITJM. 



Leaves never with spine-tipped teeth. 

 Leaves deeply lobed. 



Flower head one on each stem; pappus of bristles 8. ERIGERON. 



Flower heads several or many; pappus not of bristles. 



Heads? to 10 mm. broad; plants annual 21. MATRICARIA. 



Heads 5 mm. l)road or less. 

 Bracts distinct; pappus of bristles; leaves alternate . . 23. ARTEMISIA. 

 Bracts partly united; pappus none; leaves opposite ... 14. AMBROSIA. 

 Xeaves entire or toothed. 

 Leaves not white-hairy. 

 Leaves linear or nearly so. 



Plants covered with sticky hairs, ill-scented 17. MADIA. 



Plants without sticky hairs, not ill-scented 8. ERIGERON. 



Leaves lanceolate to triangular or broader. 



Bracts 5; heads about 4 mm. high 13. IVA. 



Bracts 10 or more; heads much larger. 

 Bracts very obtuse; pappus brownish red; leaves alternate. 



4. PYRROCOMA. 

 Bracts acute; pappus white or yellowish. 



Plants nearly glabrous; heads short-stalked; bracts very unequal in 



length 1. COLEOSANTHTIS. 



Plants hairy; heads long-stalked; bracts about equal in length. 



25. ARNICA. 

 2048—21 13 



