( 337) 
Specimens examined: Elizabeth Lake, Liebre Mountains Ab- 
rego 
Pass, Abrams €F McGregor oe San Bernardino, Parish, March, 
1902; San Dieguito River, near San Dieguito (Bernardo), Abrams 
3370; Calexico, G. D. Abrams, Feb., 1910. 
3. PopuLus TREMULOIDES Michx Fi. Bor. Am. 2: 243. 1803. 
Type locality: “Hab. in Cunade et Noveboraco.” 
Distribution: The quaking aspen is distributed through the 
Canadian Zone of California, and extends from San Pedro Martir 
northward to Alaska, hence across the northern part of the con- 
tinent, ranging southward along the mountains to New Mexico 
and Pennsylvania. Only one locality has been discovered in 
southern California, viz., Grinnell (Univ. Calif. Pub. Zoology 5: = 
1908) a several groves “on the west side of the u 
Fish Creek Canyon, north of San Gorgonio Peak, at altitudes of 
7000 to 7600 feet 
2. SALIX. WILtow. 
Stamens 3 or more; bark furrowed; 
Leaves green on both surfaces; pee glandular; a often pubescent, 
. &. vallicola 
Leaves pale beneath; capsule glabro 
Petioles with plunde near the oe o the blade; stipules conspicuous, 
glandular. 22 astandra. 
Petioles and stipules not glandular, the latter eancag. 
. S. laevigata. 
Stamens 2; bark not furrowed; trees or shrubs. 
Scales of the ament black or black-tipped. 
Ovary and capsule glabrous 
Leaves entire or remorly and obscurely serrate, becoming rusty- 
glaucous beneath; scales pubescent or ao illous. 
. S. lastolepis. 
Leaves finely serrate, becoming smooth and pale beneath scales 
long-villous. 5. S. Patsoni. 
Ovary and capsule pubes 
Aments appearing before the leaves; styles se 
. S. Scouleriana. 
Aments appearing with the leaves; styles ee 
7. S. glaucops, 
Scales of the ament pale. 
Ovary glabrous; leaves sparsely appressed-pubescent. 
8. 
Ovary pubescent at least sparsely so when young; leaves more or 
less densely silky. g. S. argophylla, 
