RYDBERG: Rocky MOUNTAIN FLORA 549 
CoLorapo: Red Cliff, Eagle Co., July 17, 1902, Osterhout 
2706 ; Tennessee Pass, July 28, 1902, Osterhout 2640. 
The first of these specimens was associated with Carduus 
griseus, Osterhout 2707 (the next number), collected at the same 
date and locality. C. griseus was collected at Red Cliff in 1906 
also, Osterhout 3362. C. scopulorum, the other supposed parent, 
is rather common throughout the mountains of Colorado. 
CARDUUS GRISEUS X PARRYI 
Carduus araneosus Osterhout, Bull. Torrey Club 32: 612. 1905. 
Osterhout in the original description of Carduus araneosus 
suggests the relationship with C. Parryt. C. araneosus differs 
from that species mainly in the less greenish corollas, the stouter 
and broader spines of the bracts, and the grayish under surface 
of the leaves. These characters suggest C. griseus, but the in- 
volucral bracts are decidedly arachnoid-pubescent and the inner 
bracts are more or less dilated above and erose. The following 
specimens belong here: 
CoLorabo: Red Cliff, Eagle Co., June 26, 1900, Osterhout 
2169; and also Aug. 16, 1906, Osterhout 3363; Boreas, July 24, 
1897, Crandall 2806; without locality, J. Wolf 459 (Wheeler Exp.). 
The first two specimens were collected at Red Cliff, where 
also two numbers of C. griseus (see under preceding hybrid) and 
one of C. Parryi, viz., Osterhout 2708, were collected. 
CARDUUS OREOPHILUS X SCOPULORUM 
This resembles C. scopulorum in the heads crowded at the ends 
of the stem, the arachnoid involucres and general habit; but the 
leaves are broader, with fewer lobes; the involucral bracts are 
broader at the base, and the flower-cluster not nodding. In 
these characters it approaches C. oreophilus, but it has less deeply 
dissected leaves with broader ene: and the inflorescence is much 
more arachnoid. 
CoLorapo: Silver Plume, hoe: 23, 1895, Shear 4948 and 4960. 
Carduus oreophilus also was collected at Silver Plume the same 
day by Shear, no. 3258, and also by Rydberg on the following day. 
C. scopulorum is common in the upper part of Clear Creek above 
Silver Plume. In the herbarium of the Garden there is one speci- 
