24G Nelson: New Plants from Wyoming 



C. cliroinosa is widely distributed in the desert region of south- 

 central \V>-oming and several collections of it show no remarkable 

 variation. The following are some of the collections of it : Lcroy, 



no. 4577, June 7, 189S ; Green River, Sweetwater ( 

 June 14, 189S ; Ft. Steele, Carbon Co., no. 5380, J 



18, 1898. 



Erigeron pinnatisectus (Gray) 



'positiis pi 



90. 



ipositus 



to keep up a cumbersome nomenclature that is neither necessary 

 nor justified by the plant. There are sufficient forms that must of 

 necessity be held as varieties of that species, w^ithout including a 

 form so decidedly at variance with the others. E. pinnatisectus in 

 its comparatively simple root-system ; its fewer, glabrate leaves and 

 stems; its pinnately dissected leaves, and its numerous, long, 

 purple rays is strongly in contrast with the tufted, compact habit ; 

 the trifid or multifid leaves ; the rather conspicuous pubescence, 



and the white rays of the other. 



E. pinnatisectus mostly occurs at higher altitudes than E. coni- 

 positus and consequently is less frequently collected but, neverthe- 

 less, it is fairly well represented in the herbaria. Professor C. S. 

 Crandall's specimens from the head waters of leaver Creek, Colo., 

 and the writer's no. 18 16, LaPlata Mines, Medicine Bow Moun- 

 tains, w^cll illustrate it. 



Erigeron melanocephalus 



if. 



in part ; E. siniph 



Greene, Fl. Fran. 387. in part (?) ; E. uniflorus indanoccpJialus 

 Aven Nelson, First Rep. Fl. Wyo. 131 and 206. 



Main root woody, more or less branched, giving rise to numer- 

 ous fibrous ones : caudex thick and nearly simple or more or less 

 branched, the branches short: stems few to several (often 10 or 

 more), slender, erect, 5-15 cm. high, monocephalous, pubescent 

 with purplish hairs : leaves numerous on the crowns, nearly sessile 

 to long-petioled, blade elliptic to narrowly oblong, 2-5 cm. long 

 (including the petiole), almo.st glabrous ; stem leaves several, 

 broadly linear, acuminate, 2-3 cm. long, pubescence similar to 

 that of the stem : heads large, when fully expanded 3 cm. broad : 

 involucral bracts involved in a dense, dark-purple wool, the hairs 

 of which consist of purple and tran.sparent cells alternately ar- 



