202 COMPOSITE. (COMPOSITE FAMILY.) 



nately incised : heads rather few-flowered, less than 2 lines long, greenish, 

 hardly pubescent. — Prairies, the Uakotas to Illinois. 



13. A. longifolia, Nutt. Stem 2 to 5 feet high: leaves entire, at first to- 

 mentulose, but usually glabrate above, white-tomentose beneath, linear or 

 linear-lanceolate (1 to 5 lines wide) : heads usually canescent, 2 or 3 lines 

 long. — Minnesota and Nebraska to Montana. 



= = Not bo tall : leaves more or less cleft or divided, or when entire compara- 

 tively short, not filiform nor narrowly linear. 

 a. Involucre from canescent to woolly, 12 to 20-fiowered. 

 1 14. A- Ludoviciana, Nutt. A foot to a yard high, simple or with virgate 

 branches, sometimes paniculate, completely and somewhat fiocculentl y white-tomen- 

 tose, or upper face of leaves sometimes early glabrate and green : leaves from 

 linear-lanceolate to oblong, sometimes nearly all undivided and entire ; com- 

 monly the lower with u. few coarse teeth or incisions, or 2 to 3-cleft, or irregularly 

 3 to 5-parted into lanceolate or linear entire lobes : heads glomerately paniculate, 

 not over 2 lines long : involucre woolly-tomentose. — Including also var. gnapha- 

 lodes, Torr. & Gray. Across the continent from the west to Michigan and 

 Illinois. 



15. A. Mexicana, Willd. Paniculately branched, 2 to 4 feet high, less 

 tomentose : leaves narrow-lanceolate to linear, commonly attenuate, some 3 to 

 5-cleft or parted ; radical cuneate, incisely pinnatifid or trifid : heads very nu- 

 merous in an ample loose panicle, many pedicellate, 1 to 2 lines long : involucre 

 arachnoid-canescent or glabrate, largely scarious. — A. Ludoviciana, var. Mexi- 

 cana, Gray. Dry plains, from S. Nevada, S. Colorado, and Arizona to Texas 

 and Arkansas. 



b. Involucre glabrous, 20 to 40-flowered. 



16. A. franserioides, Greene. Glabrous throughout, or minutely and 

 obscurely puberulent : stem rather stout, 2 or 3 feet high : leaves compara- 

 tively ample, green above, pale and barely cinereous beneath ; lower bipinnately 

 and upper simply pinnately parted into lanceolate-oblong obtuse entire or 2 to 3- 

 cleft divisions and lobes : heads numerous, loosely racemose on the branches of the 

 leafy elongated panicle, 2 or 3 lines broad. — Bull. Torr. Club, x. 42. Moun- 

 tains of S. Colorado, New Mexico, and Arizona. 



17. A. discolor, Dougl. A foot high, mostly slender, glabrous or gla- 

 brate except the lower face of the leaves : these white with close cottony tomen- 

 tum, 1 to 2-pinnately parted into narrow linear or lanceolate entire or sparing!// 

 laciniate divisions and lobes : heads glomerate in an interrupted spiciform or virgate 

 panicle, 1 or 2 lines high. — Mountains of British Columbia and Montana to 

 Utah, Nevada, and California. 



Var. inoompta, Gray. Stouter, with coarser or less dissected leaves, 

 having mostly broader lobes, or the upper entire. — Synopt. PI. i. 373. A. in- 

 compta, Nutt. Mountains from Wyoming and Montana to California and 

 Washington. 



= = = Rather low: leaf-divisions narrowly linear or filiform : heads 15 to 20- 

 flowered, in a narrow thyrsoid or spiciform panicle. 



18. A. Wrightii, Gray. Cinereous or canescent, or radical shoots some- 

 times white-tomentose, 10 to 20 inches high, very leafy up to the panicle : 



