550 Rydberg : Rocky Mountain flora 



men from near Gray's Peak, Shear 4734, collected on the same 

 date as 4Q48 and 4g6o. 



Carduus coloradensisXundulatus 

 With the specimen cited below, Mr. Osterhout sent a slip of 

 paper on which is written: "Do not think this is Carduus undu- 

 latus — do not know what it is." It resembles C. undulatus, the 

 flowers being red, although paler, the bracts having a glandular 

 dorsal ridge, and the general habit and leaf-form being similar, but 

 the dorsal ridge is very inconspicuous. It resembles perhaps more 

 C. coloradensis in habit, in the form of the bracts, and the lanceo- 

 late twisted tips of the innermost of these. There is also an indi- 

 cation of arachnoid hairs on the stem, but the corollas are pink, 

 not dirty white, and there is an evident though narrow dorsal ridge 

 towards the ends of the bracts. 



Colorado: Wolcott, Eagle Co., July 11, 1902, Osterhout 2653. 

 Mr. Osterhout collected also C. coloradensis at the same date 

 and locality, viz., 2651. 



Carduus filipendulus Xochrocentrus 

 Carduus dispersus Osterhout MS. 



This has the large heads and the long spines of C. ochrocentrus 

 but the broad non-decurrent leaves and dark green glabrate upper 

 surfaces of C. filipendulus. 



Colorado: Home, Larimer Co., July 29, 1904, Osterhout 28q8. 



Both of the supposed parents are common in Larimer County. 

 Mr. Osterhout doubts that this can be a hybrid between the two 

 supposed parents given above, as he has not seen either growing 

 so far up in the mountains. 



Carduus Flodmanii Xmegacephalus 

 This specimen cited below was determined as Carduus Flod- 

 manii, but its leaves are much broader and with shorter and broader 

 lobes, the heads are larger, and their bracts more glutinous than in 

 the typical C. Flodmanii. The plant is almost exactly inter- 

 mediate between that and C. megacephalus . 



Colorado: Fort Collins, July 30, 1904, Osterhout 2Q03. 



Both of the supposed parents are common around Fort Collins. 



