CARDUACEAE. 383 



Leaves all entire or the lower merely toothed. 



V. Gnaphaloides. 

 Leaves at least the lower ones pinnately divided or lobed. 



Divisions of the leaves not narrowly linear or filiform ; margins 



scarcely revolute. VL Diversifoliae. 



Divisions of the leaves narrowly linear to filiform ; margins 

 revolute. VIL Stenophyllae. 



Involucres in age glabrous, only slightly tomentose when young. 



VIIL VULGARES. 



Plant shrubby ; leaves cuneate, 3-toothed at the apex. 



IX. Bigelovianae. 

 Heads homogamous ; i. a., flowers all alike, hermaphrodite and fertile ; plants 

 shrubby. X. Tridentatae. 



I. Dracunculoides. 



Plants frutescent only at the base ; heads rather many-flowered, hemispherical, 

 over 1.5 mm. in diameter. 

 Plants glabrous, at least in age ; leaves all, except the lower ones, simple and 

 linear. 

 Leaves and bracts dark green ; heads 3-4 mm. wide ; flowers 30-40, brown. 



I. A. aromatica. 

 Leaves and bracts lighter ; heads 2-3.5 mm. wide ; flowers yellow or light 

 brown, about 20. ij. A. dracunculoides. 



Plant pubescent ; leaves nearly all pinnatifid. 



Heads 2-3 mm. wide ; bracts glabrous ; stem appressed-hairy or glabrate ; 

 flowers yellow. 

 Stem-leaves with 1-2 pairs of lateral divisions close at the base, or entire 



grayish canescent. 3. A. glauca. 



Stem-leaves pinnatifid or bipinnatifid with distant divisions, mostly green 

 at least in age. 

 Stem tall, 5-10 dm. high, very leafy, in age nearly glabrous; divisions 



of the leaves linear-filiform. 4. A. Scouleriana. 



Stem lower, 2-6 dm. high ; divisions of the basal leaves linear-oblanceo- 

 late, more or less canescent. 5. A. Forwoodii. 



Heads 4-5 mm. wide ; bracts and stem at least when young with long silky- 

 villous loose hairs; flowers brown. 6. A. spithamaea. 



Plant shrubby ; heads few-flowered, 1-1.5 mm. in diameter ; divisions of the 

 leaves filiform. 7. A, Mifolia. 



II. Frigidae. 



Heads numerous, 4-5 mm. wide; bracts light brown; plants ^usually comparatively 



tall, 3-8 dm. high. 8. A. frigida. 



Heads few, 6-12 mm. in diameter; bracts with dark brown or blackish margins; 

 plant low, 1-2 dm. high. 

 Heads several, spicately or racemosely disposed ; corolla pubescent ; basal 



leaves and lower stem-leaves bipinnatifid. 9. A. scopulorum. 



Heads solitary or 2-4 in a close cluster ; corolla glabrous or nearly so ; basal 

 leaves pinnatifid with short divisions. 10. A. Pattersonii. 



III. Annuae. 



One species. 11. A. biennis. 



IV. Arcticae. 

 Plant pubescent. 12. A. saxicola. 



Plant glabrous. 13- ^- Parryi. 



V. Gnaphaloides. 



Leaves in age glabrate above. 14. A. silvicola. 



Leaves permanently tomentose on both sides. 



Heads erect, peduncled, 4-5 mm. wide; flowers brown. 15. A. natronensis. 



Heads nodding or spreading, 4 mm. or less wide. 



