CROWFOOT FAMILY 287 



Styles 4-6 mm. long; leaves 3-4 times ternate; segments narrowly linear. 



6. A. Drummondii. 

 Stylos subulate, persistent; heads of fruit from rounded oblong to cylindric; 



involucral leaves long-petioled. 

 Heads elongate, cylindric; styles about 1 mm. long; flowers usually subumbel- 



late. 7. A. cylindrica. 



Heads of fruit rounded-oblong ; styles about 2 mm. long ; flowers truly cymose. 

 Petals greenish white, 1 cm. long or less; styles in fruit divergent. 



8. A. virginiana. 



Petals white, 1.5 cm. long; styles suberect. 9. A. riparia. 



Achenes not villous. 



Achenes wing-margined; plant stout. 



Sepals yellow; styles very long, reflexed. 10. A. Richardsoni. 



Sepals white or pink; styles not reflexed. 



Flowers cymose; achenes sparsely hirsute when young, sessile; styles long, 



straight. 11. A. canadensis. 



Flowers subumbellate ; achenes glabrous, stipitate; styles short, curved. 



12. A. zephyra. 



' Achenes not wing-margined, pilose; style minute; plant slender; flowers solitary. 



13. A. Piperi. 



1. A. tuberosa Rydb. Stem 1-3 dm. high; basal leaves twice ternate; 

 divisions rhombic-cuneate in outline, ternately cleft and toothed; involucral 

 leaves similar, but short-petioled ; peduncle solitary or a second one with a smaller 

 involucre; sepals white or purplish, oblong-linear, 12 cm. long; head of fruit 

 ellipsoid; achenes densely woolly; style filiform, about 1.5 mm. long. A. spheno- 

 phylla Britton, not Poepp. Dry plains and hills: N.M. -Utah -Calif. L. 

 Son. F-Ap. 



2. A. parviflora Michx. Stem 5-20 cm. high; leaves ternate, thick, and 

 firm, glabrous above, silky-strigose beneath; divisions cuneate, 1-2 cm. long; 

 sepals white or tinged with bluish or rose, oval, 8-18 mm. long; head of fruit 

 spherical. In arctic-alpine situations: Lab. Out. Mont. Colo. Alaska; Asia. 

 Mont. Subalp. My-Au. 



3. A. tetonensis Porter. Stem silky, 1-3 dm. high, 1-3-flowered, the 

 secondary peduncles with smaller involucres; leaf -blades twice ternate, 2-5 cm. 

 broad; involucral leaves similar, but sessile; sepals oval, 6-10 mm. long, often 

 dark purple, more rarely white, and tinged with blue on the outside; head of 

 fruit hemispherical, 10-15 mm. in diameter. A. stylosa A. Nels. Mountains: 

 Alta.Wyo. Utah Wash. B.C. Submont.Subqlp. Jl-Au. 



4. A. lithophila Rydb. Stem 1-2 dm. high, sparingly pubescent with long 

 silky hairs; basal leaves thickish, shining, somewhat glaucous; divisions 

 about 3 cm. long, deeply 3-cleft, again cleft and toothed; sepals silky, ochroleu- 

 cous, tinged with blue, 12-15 mm. long, broadly obovate or oval; head of fruit 

 globose. Rocky mountain tops: Mont. Wyo. 'Utah. Submont. Subalp. Jl- 

 Au. 



5. A. globosa Nutt. Stem 2-5 dm. high, silky- villous, 1-3-flowered; leaf- 

 blades 5-12 cm. broad, thrice cleft; sepals oval, 6-12 mm. long, pink or purplish 

 or ochroleucous, tinged with bluish on the outside; heads of fruit globose or ovoid, 

 10-12 mm. in diameter. A. multifida Hook., in part, not Poir. Meadows and 

 hillsides: Alaska Calif. Colo. S.D. Sask. Mack. Plain Subalp. My-S. 



6. A. Drummondii S. Wats. Stem 1-2 dm. high, usually 1-flowered, silky- 

 hirsute; leaf -blades 2-6 cm. broad, silky-hirsute; sepals oval, 8-10 mm. long, 

 tinged with blue; heads of fruit spherical, about 1 cm. thick; achenes densely 

 woolly. High mountains : B.C. Alta. Ida. Calif. Mont. -Subalp. Jl-Au. 



7. A. cylindrica A. Gray. Stem 3-6 dm. high, 1-10-flowered; leaf-blades 

 strigose-pubescent, 3-8 cm. wide, ternate or quinnate; divisions rhombic-cuneate, 

 3-cleft and again cleft or toothed, w T ith ovate or lanceolate teeth or lobes; invo- 

 lucral ones similar, clustered together with those of the secondary peduncles, 

 the lowest node of which usually is very short or obsolete, the inflorescence there- 

 fore becoming umbelliform; sepals greenish white, oblong, 8-10 mm. long; heads 

 in fruit 2-4 cm. long, about 1 cm. thick. Meadows, hillsides, and river banks: 

 N.B.N.J. Ariz. B.C. Plain Submont. Je-Au. 



8. A. virginiana L. Stem 6-10 dm. high, hirsute, 1-7-flowered; leaf-blades 

 10-15 cm. broad, ternate or quinate, more or less silky-hirsute; divisions rhom- 



