202 COMPOSITE. (COMPOSITE FAMILY.) 



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

 hardly pubescent. Prairies, Dakota 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. 



= =s 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, 1 2 to 20-Jlowercd. 



14. A. LudOViCiana, Nutt. A foot to a yard high, simple or U'ith virgate 

 branches, sometimes paniculate, completely and somewhat jlocculently 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 a 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 icoollij-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 W-fiowered. 



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

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

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

 Washington Territory. 



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

 fiowered, in a narrow thyrsoid or spiciform panicle. 



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

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



