KEY TO THE SPECIES 85 



cephalous ; involucral bracts linear ; rays numerous, white. Sterile slopes and 

 ridges. 



» * Leaves narrow, entire ; plants tufted or spreading. 



^- Conspicuously hirsute-pubescent ; branched-spreading from the crown or 

 crowns of a tap-root. 



3. Erigeron pumilus Nutt. (Low Eeigeron). Stems leafy, spreading- 

 assurgent, 7-15 cm. longi; basal leaves spatulate-linear ; stem-leaves linear ; heads 

 15-20 mm. broad ; rays 50-80, white. Sandy plains and valleys. 



■I- +- Pubescence minute ; plants green ; rays white. 



3. Erigeron Eatoui Gray (Eaton's Erigeron). Low and strongly tufted, 

 the numerous short, slender stems and linear leaves crowded on the crowns of the 

 branched woody caudex ; leaves 2-5 cm. long, surpassed by the peduncles ; heads 

 about 15 mm. broad, usually solitary, sometimes 1 or 2 smaller accessory ones ; 

 involucre minutely hirsute, the bracts dark green on the midrib ; rays few (15-30). 

 Frequent and abundant on stony gravelly slopes. 



4. Erigeron flagellaris Gray (Running Erigeron). More or less branched 

 below, the stems slender and flexuous, spreading, 1-4 dm. long ; the lower leaves 

 narrowly oblanceolate, becoming smaller and narrower upward, reduced to bracts 

 above ; peduncles naked, monocephalous ; rays very numerous and narrow, 

 sometimes pinkish. Moist draws and banks. 



-t- ^- -J- Glandular or granular ciliate-pubescent ; rays violet or purple. 



5. Erigeron glandulosus Porter (Glandular Erigeron). Stems and leaves 

 crowded on the thick crowns of the caRspitose caudex, 10-85 cm. high ; leaves from 

 narrowly spatulate to linear, 3-6 cm. long ; stems leafy below, naked pedunculate 

 above with a single showy head ; rays 40-50. Stony slopes ; foothills and moun- 

 tains. 



* * * Leaves large, some of them coarsely toothed, plants erect. 



6. Erigeron PhiladelpUlcuB L. (Common Fleabane). Hairy ; stem leafy, 

 branching above, bearing several small heads ; leaves thin, oblong, the upper ones 

 smoothish, clasping by a heart-shaped base, mostly entire, the lowest spatulate 

 and toothed ; rays innumerable and very narrow, rose-purple or flesh-color. 

 Moist ground. 



3. ACHILLEA (Yarrow) 



Perennial herbs with erect stems, finely dissected pinnatifld alternate leaves, 

 small heads in corymbs at the summit of stem and branches, campanulate invo- 

 lucres of unequal imbricated bracts, yellow disk, and a few broad white rays. 



1. Achillea lanulosa Nutt. (Western Yarrow). Somewhat woolly pubes- 

 cent, 2-5 dm. high ; leaves finely bipinnate ; cyme dense and flat-topped ; invo- 

 lucral bracts with green, keeled midrib and thin brownish margins, the chaff on 

 the receptacle membranous. Common ; from the plains to the mountain-tops. 



4. CH-iENACTIS 



Perennial herbs with alternate dissected leaves, rather large rayless heads in 

 open irregular terminal cymes. 



1. Chienactis Douglasil H. & A. (Douglas's CH.a:NACTis). More or less 

 whitened with ^hort woolly floccose pubescence, sometimes becoming glabrate, 

 branched from the base and sparingly upward, 1^ dm. high ; leaves bipinnately 



