556 Rypserc: Rocky MOouNTAIN FLORA 
to find two species that would produce a combination of characters 
found in C. oreophilus. A mixture of four species, C. pulchellus, 
C. spathulatus, C. scopulorum and C. coloradensis might do it. 
I think therefore that it is best to regard it at present as distinct. 
Under Carduus bipinnatus (Eastw.) Heller, in the New Manual, 
we find: C. pulchella{us], C. truncatus Greene(?) and C. spathulatus 
Osterh. The only true synonym is C. truncatus Greene. C. 
pulchellus is related to it, but the leaves are white-tomentose 
beneath. C. spathulatus Osterhout is related to C. griseus, though 
its involucral bracts are much shorter. The plant resembles 
closely C. americanus, but the bracts are not at all fimbriate. - 
Carduus Tracyi Rydb. is, in the New Manual, made a syn- 
onym of C. Nelsonii Pammel (Pammel did not use the generic 
name Carduus and the page is wrongly cited), while the latter is 
kept distinct from C. plattensis Rydb. 
A botanist with broad limitations of species might regard 
Carduus plattensis, C. Nelsonii, C. Tracyi, C. brevifolius, and C. 
palousensis as one species. They are all closely related but each 
has a definite range of itsown. C. plattensis belongs to the sandy 
regions of Nebraska, Kansas, and northeastern Colorado; C. 
Nelsonii, as far as I know, is found only in Wyoming; C. Tracyt 
in southern Colorado; C. brevifolius in Wyoming and Montana; and 
C. palousensis in western Idaho and eastern Washington and 
Oregon. Carduus Nelsonti and C. platiensis are the most closely 
related of the four; the only difference I can find is that C. plattensis 
has the inner bracts prolonged into linear lanceolate, spreading, 
more or less crisp tip, a character not found in the rest. The 
characters given by Nelson in the key to distinguish C. Nelsonti 
and C. plattensis are useless, because the characters assigned to 
the latter are not true. 
Under Carduus filipendulus (Engelm.) Rydb., in Coulter & 
Nelson’s New Manual, are given as synonyms: C. Flodmanii 
Rydb. and C. oblanceolatus Rydb. The description of C. 
filipendulus is a verbatim copy of my description of C. 
Flodmanni. Little could be said against this, if the two 
were the same, but this is not the case. In the key, Professor 
Nelson distinguishes C. filipendulus from C. undulatus, C. mega- 
cephalus, and C. ochrocentrus by the characters: ‘‘Leaves becoming 
