Rydberg: Rocky Mountain flora 553 



.Carduus Butleri X Kelseyi 



The leaves of the two supposed parents are very similar, so 

 the differences are mostly found in the inflorescence and the in- 

 volucral bracts. See under the description of Carduus Butleri. 



The supposed hybrid has the inflorescence of C. Kelseyi, the 

 bracts of C. Butleri, but slightly arachnoid-hairy. 



Montana: Rost Lake, July 28, 1908, Butler 703. 



Carduus Butleri was collected at the same locality and on the 

 same date, Butler 6'jy; and C. Kelseyi three days later a little 

 higher up in the mountains, Butler jgS. 



Carduus EatoniXolivescens 



Cnicus Eatoni A. Gray included several forms. Three of 

 these had been distinguished b}^ D. C. Eaton, who, however, had 

 applied wrong names for two of them. The first of the three 

 Eatonian synonyms cited by Dr. Gray is Cirsium eriocephalum 

 var. leiocephalum. Dr. Gray's description also applies principally 

 to this. Hence Carduus leiocephalus (D. C. Eaton) Heller becomes 

 a synonym. Cirsium foliosum D. C. Eaton, I think, is the same 

 as Carduus nevadensis Greene and C. Drummondii D. C. Eaton is 

 a Nevada plant, almost identical with C. oreophilus of Colorado. 



The supposed hybrid under consideration resembles C. Eatoni 

 in general habit, but the leaves have fewer and deeper lobes and 

 are grayish tomentose beneath, and the involucres have shorter 

 and weaker spines. It differs from C. olivescens in the broader 

 segments of the leaves, the narrower bracts, of which the outer are 

 spinulose-ciliate as in C. Eatoni. 



Utah : Aquarius Plateau, Aug. 4, 1905, Rydberg & Carlton 7422. 



Carduus olivescens also grew on the Aquarius Plateau. The 

 type of it was collected the following day and bears the number 

 7450. C. Eatoni is common in the same region, although Carlton 

 and myself did not preserve any specimens from the Aquarius 

 Plateau. 



Carduus pulchellus X undulatus 



This most resembles Carduus pulchellus in habit, but the in- 

 volucres are more hemispheric instead of truly campanulate, the 

 bracts are broader and with a narrow glutinous ridge, and the inner 



