RYDBERG: NOTES ON ROSACEAE 503 
leaves, scarcely 5 mm. long, is referred doubtfully to this species. 
It is Vernon Bailey 2019 of the Death Valley expedition. 
Cercocarpus arizonicus Jones. This species is much more local 
than C. intricatus. It is closely related to it, perhaps not distinct 
If C. hypoleucus were found in the region this might be a hybrid 
between that species and C. intricatus. 
Utan: Deep Creek, 1891, M. E. Jones; Tropic, 1894, Jones. 
NEvapDA: Rock Mountains, 1898, Purpus 6336?. 
HYBRIDS 
Mr. Coville has collected specimens which are without doubt 
a hybrid between C. ledifolius and C. macrurus. A specimen of 
the hybrid and one of each of the two parents is mounted on the 
same sheet, his mo. 1523 in the National Herbarium. When these 
two species hybridize, it would be expected that some of the more 
closely related species might do so. This may explain some of 
the intermediate forms between C. betuloides and C. Douglasii, 
between C. montanus and C. flabellifolius, and between C. ledifolius 
and C. intricatus. 
Also a specimen collected by M. E. Jones at Silver Reef in 
1894 seems to be a hybrid of C. ledifolius and C. arizonicus. A 
specimen of the latter is included under the same number, 5149k, 
and C. ledifolius is found in the region. 
NEw York BOTANICAL GARDEN 
