RyDBERG: Rocky MouNTAIN FLORA 557 
green and glabrate on the upper side” against ‘‘Leaves permanently 
tomentose on both sides.’’ The glabrate character is correct 
as far as C. filipendulus in concerned and was the reason why 
Dr. Gray associated it with C. altissimus; but it is not true of 
C. Flodmanii, for in that species the tomentum is as permanent 
as in C. undulatus and C. ochrocentrus and far more so than in 
C. megacephalus. In the key C. filipendulus is characterized, 
but the description is of C. Fledmanii under a wrong name. Dr. 
Gray included C. Flodmanii in his Cnicus undulatus canescens. 
Professor Nelson has admitted a variety Carduus undulatus 
canescens (Nutt.) Porter. Evidently this was unknown to him 
for he simply copies Gray’s characterization of Cnicus undulatus 
canescens. Some years ago, while visiting the Gray herbarium, 
I was curious to see what Gray meant by this variety. I found 
that it contained a mixture of Carduus Flodmanii, C. oblanceolatus, 
another related species of Arizona, and Cirsium brevifolius Nutt. 
The last is a yellow-flowered species related to Carduus Nelsonii 
and C. plattensis, and antedates both. Of these C. Flodmanii 
agrees best with the description of Cirsium canescens Nutt., and it 
might be that species. I have seen, however, a specimen of another 
species with strong erect involucral spines, which bore the name 
Cirsium canescens in Nuttall’s own handwriting. Whether that 
specimen was the type or not I do not know, but I have adopted 
the name Carduus canescens for that species. Pammel in his 
treatise on the Iowa thistles adopted the name Cnicus canescens 
for Carduus Flodmanii. Uf Nelson had followed him, I would not 
have made any criticism, as there is some doubt as to which the 
name canescens belongs to, C. Flodmanii or the species for which 
I have adopted it. 
Professor Nelson has also omitted all the Utah species described 
by Marcus E. Jones, although most of them belong to the range 
of the New Manual. 
CENTAUREA and ARCTIUM 
Neither of these two genera are included in the New Manual, 
although C. Cyanus has been collected at several places in Mon- 
tana, C. solstitialis L. at Salt Lake City, Utah, and A. minus 
Schk. in Colorado. 
New York BoTaNICAL GARDEN, 
