202 COMPOSITE. (COMPOSITE FAMILY.) 



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

 hardlij pubescent. — Prairies, the Dakotas 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 so tall : leaves more or less cleft or diiiided, or when entire compara- 

 tivelt/ shorty notfliform nor narroirlij linear. 

 a. Involucre from canescent to icooUij, \2 to 20-flowered. 

 1 14. A. LudOViciana, Nutt. A foot to a yard high, simple or icith virrjate 

 branches, sometimes paniculate, completeli/ and somewhat focculentltj tchite-tomen' 

 lose, or upper face of leaves sometimes early glal)rate and green : leaves from 

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

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

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

 not over 2 lines long: involucre n-ooll y-tomentose. — Including also var. gnapha- 

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

 Illinois. 



15. A. Mexieana, 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 cmieate, incisely pinnatifd or trifid : heads very nu- 

 merous in an ample Loose panicte, many peaicellate, 1 to 2 lines long : involucre 

 arachnoid-cane scent or glabrate, largely scarious. — ^4. Ludoviciana, var. ]\lexi- 

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

 and Arkansas. 



b. Involucre glabrous, 20 to 40flowered. 



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 sparingly 

 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. ineompta, Gray. Stouter, with coarser or less dissected leaves, 

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

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

 Washington. 



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

 fiowered, in a narrow thyrsoid or spiciform panicle. 



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

 times white-tomentose, 10 to 29 inches high, very leafy up to the panicle : 



