86 KEY TO THE SPECIES 



dissected, the lobes from linear to short oblong ; heads often nearly 2 cm. high ; 

 involucre campanulate, its bracts slightly or not at all imbricated ; achenes linear, 

 pubescent ; the pappus of thin fringed gUstening scales. Open stony and sterile 

 slopes. 



5. PETASITES 



Perennials from thick rhizomes, with scaly scapose stems, large radical leaves 

 on stout petioles and white flowers in corymbiform racemes. 



1. Petasites sagittata (Pursh) Gray (Sweet Coltsfoot). Somewhat woolly- 

 pubescent ; stems erect, 1-3 dm. high, with several alternate erect foliaceous 

 lanceolate bracts ; leaves large, deltoid-oblong to reniform-hastate, very white- 

 tomentose beneath, developing a little later than the stems, becoming 1-3 dm. 

 long ; involucre campanulate, its bracts in a single series ; corollas very slender, 

 the outer with a narrow white llgule. Marshy mountain meadows. 



6. RUDBECKIA (Cone-flower) 



Herbs with alternate leaves, showy terminal heads, leaf-like and spreading 

 involuoral scales, long yellow rays, hemispherical to oblong or conical dark disk, 

 with short chaff. 4-sided smooth achenes, and no pappus. 



1. Riidbeckia flava Moore (Western Black-eyed Susan). Hirsute or 

 strigose ; stems simple, straw-colored, purple-dotted, 3-5 dm. high ; leaves oblong, 

 lanceolate to nearly linear, tapering into a margined petiole ; heads solitary, long- 

 peduncled ; involucral bracts oblong-linear ; rays about 25 mm. long, linear-oblong, 

 yellow. Frequent ; plains and foothills. 



2. Rudbeckia ampla Av'en Nelson (Larsb Cone-flower). Perennial, from 

 horizontal rootstocks ; stems erect and branched, striate, 1-2 m. high ; leaves large, 

 compoundly trifoliate ; leaflets ovate, 3-cleft, coarsely and irregularly serrate ; 

 heads large, terminating the branches, involucral bracts ovate to oblong ; rays 

 6-12, conspicuous, 3-5 cm. long ; disk cylindrical ovate, 2^ cm. high. Moist copses. 



7. HELIANTHUS (Sunflower,) 



Rather coarse herbs, the following being annuals with 3-nerved leaves alter- 

 nate above and opposite below, the showy peduncled heads which terminate the 

 branches having yellow ray s and a broad flat brownish or purpHsh disk, an involucre 

 of spreading attenuate bracts, and thick oblong somewhat 4-angled achenes. 



1. Helianthus annuus L. (Common Shnflowke). Roughish pubescent or 

 hispid ; under favorable conditions becoming large and freely branched ; leaves 

 broadly ovate, 1-2 dm. long ; heads in the wild plant 6-13 cm. broad ; bracts of the 

 involucre ovate or narrower, ciliate-hispid ; bracts or chaff of the receptacle Sclef t. 

 Waste grounds and on the plains. From this has been derived the much larger 

 cultivated forms. 



2. Hellanthus petiolaris Nutt. (Prairie Sunflower). Smaller, quite 

 similar, hirsute, sparingly branched above ; leaves mostly ovate-lanceolate, 4-8 

 cm. long on slender petioles, entire or nearly so ; heads smaller, only 3-5 cm. 

 broad. Sandy plains and river bottoms. 



8. BALSAMORRHIZA (Balsam-root) 



Perennials from thick deep-set balsamic scented roots, with tufted radical 

 long-petloled leaves, and few-leaved or scapose erect stems bearing large solitary 

 heads of yellow flowers. 



