RyDBERG: Rocky MounrTAIN FIORA 555 
ing synonyms: ‘‘Cnicus eriocephalus Gray, Carduus scopulorum 
Greene l.c., C. Tweedyi Rydb. l.c., C. araneosus Osterh. * * * C. 
Eatonti Gray, *** C. canovirens Rydb. l.c. ( ?) C. pulcherrimus 
Rydb.” Of these the two first are pure synonyms. CarduusTwee- 
dyi is a related red-flowered species (see page 552). C. Eatoni, 
as I understand it and limited to C. eriocephalus var. letocephalus 
D.C. Eaton, is a good species, forming a group by itself. C. arane- 
osus is not related to C. scopulorum but to C. Parryi, as Oster- 
hout suggested, and is probably a hybrid of that species and C. 
erosus. C. canovirens and C. pulcherrimus do not belong even 
near C. scopulorum, but to the C. undulatus group. C. canovirens 
has no very close relative. The nearest is perhaps C. canescens 
(Nutt.). Nelson once thought it a good species, distributed it 
under a manuscript name, and would have published it, if his 
attention had not been called to the fact that it was already pub- 
lished. C. pulcherrimus is most closely related to C. ochrocentrus 
and stands to that species nearly in the same relationship as 
C. undulatus does to C. megacephalus. 
Under Carduus foliosus are found the following synonyms: 
C. scariosus (Nutt.) Heller and C. coloradensis Rydb. Judging 
from Nuttall’s original description of Cirsium scariosum, it is not 
at all related to Carduus foliosus Hook. See remarks above under 
C. lacerus. Carduus coloradensis is not to be referred to C. 
foliosus. It was based mainly on Cnicus Drummondii of the 
Synoptical Flora, and is apparently the same as Carduus Drum- 
mondii of the New Manual, the corolla of which is described as 
white. The original Cirsium Drummondii T. & G., of which there 
is a duplicate in the Torrey herbarium, has rose-purple corollas. 
The only specimens I have seen from the United States, are from 
the Black Hills of South Dakota. All the others are from British 
America. 
Carduus oreophilus Rydb. is given as a synonym under C. 
Drummondii. From what is just stated it may be seen that it is 
not the original C. Drummondii and a comparison between my 
description in the Bulletin of the Torrey Botanical Club and that 
of C. Drummondii in the New Manual shows that it is not C. 
Drummondii as understood by Professor Nelson. C. oreophilus 
is very local and many things suggest a hybrid, but I have failed 
