COMPOSITAE. 277 



nearly membranaceous; ray-flowers mostly 8, neutral, yellow or 

 purple, rarely wanting; receptacle flat with deciduous mem- 

 branaceous chaff; akenes obcompressed, often winged, with 2 

 barbless subulate awns. 



Coreopsis atkiasoniana Dougl. Glabrous; stems 30-100 cm. high, erect, 

 usually branched; leaves all opposite, the lowest bipinnately parted into 

 linear lobes, reduced upward to simple linear bracts; heads cymosely panicu- 

 late; involucral bracts in two series, the outer short, the inner ovate, scarious- 

 margined, 6-8 mm. long; rays yellow, with brown bases; akenes oblong, 

 narrowly winged, bearing two short subulate teeth. In wet places on river 

 banks. 



413. WYETHIA. 



Perennial herbs; stems simple, rarely branching; leaves alter- 

 nate, mostly entire and ample; heads many-flowered, solitary or 

 few, medium or large; flowers yellow; ray-flowers elongated, 

 pistillate or fertile; pappus a chaffy crown or cup; ray -akenes 

 neither obcompressed nor laterally compressed. 



Wyethia amplexicaulis Nutt. Whole plant dark-green and glabrous, more 

 or less resinous; radical leaves oblong-lanceolate or oblanceolate, entire or 

 somewhat dentate, acute or acuminate, erect or nearly so, 15-40 cm. long, 

 narrowed at base into a short petiole; cauline shorter and relatively broader, 

 sessile and partly clasping at base; stems 30-60 cm. high, bearing a terminal 

 head and usually 1-5 smaller lateral ones, all peduncled; involucre 2-3 cm. 

 high; bracts lanceolate, acute, the outer ones longest, loose, somewhat spread- 

 ing; rays bright-yellow, about 3 cm. long; akenes clavate, 8-10 mm. long, 

 with a well developed crown, cut into small teeth and rarely bearing 1-2 awns. 

 Abundant in wet meadows. This plant is one of the so-called " compass- 

 plants." 



414. HELIANTHELLA. 



Perennial herbs ; leaves entire, opposite or the upper alternate ; 

 heads large, terminal, chiefly solitary and long-peduncled; 

 flowers yellow; ray-flowers neutral; disk-flowers perfect; recep- 

 tacle flat or convex, chaffy; pappus a pair of persistent awns or 

 chaffy teeth, and a crown of intermediate thin chaffy scales; 

 ray-akenes laterally compressed ; disk-akenes 4-angled or laterally 

 compressed, all very flat, winged when young. 



Helianthella douglasii T. & G. Rough-hairy throughout, simple or 

 branched above, erect, 60-120 cm. high; leaves opposite, or the upper alternate; 

 lower ones spatulate-lanceolate, obtuse or acute, 6-15 cm. long, the upper 

 cauline lanceolate, sessile, smaller; heads solitary and terminal or several, 

 terminating the branches; involucres 2-3 cm. broad, the bracts lanceolate, 

 hirsute-ciliate, little imbricated; rays 2-3 cm. long; akenes obovate, more or 

 less ciliate; pappus a pair of long chaffy awns, with broadened bases. Rocky 

 hillsides, common. 



415. HELIANTHUS. Sunflower. 



Coarse annuals or perennials; leaves entire or toothed, all or 

 at least the lower ones opposite; heads solitary or corymbose, 



