VOL. I1.] Flora of Yo Semite. 159 
California feed only on this plant—though I have somewhere gath- 
ered an unverified idea that they have been induced, perhaps starved 
into, eating Thalictrum. 
The laurel or bay-tree ( Umbellularia Californica ) abounds in the 
cafions usually in the form of bushes, though one tree of consider- 
able size may be seen near the foot of the lower Yo Semite Fall. 
It, however, never reaches in the Sierra Nevada such dimensions as 
we find in the Coast Range. 
Myrica Hartwegi, a rather rare wax-myrtle, though not found in 
the valley grows on the Merced below it. 
The green alder ( A/nus viridis) is extremely common as a shrub, 
about the borders of wet meadows both in the valley and on the 
heights. 
The hazel ( Corylus rostrata) and the chinquapin ( Castanopsis 
chrysophylla) abound as they do on our Tamalpais. 
The oaks of Yo Semite number three or four species. The de- 
ciduous one is Quercus Kelloggii—a black oak; the evergreen is 
QO. chrysolepis, both abundant in the valley about its margin and on 
the lower declivities. The variety vaccintfolia of the latter species 
reaches eight or nine thousand feet, gradually losing as it ascends 
the golden pubescence of the lower surface of its leaves. At the 
higher altitudes it is from two to five feet high and looks very un- 
like the type. Two other scrub oaks, QO. Brewer and Q. dumosa, 
are reported from the region but specimens are wanting. 
Of the poplars, Populus trichocarpa, known locally as ‘‘ Balm of 
Gilead,” is common in the valley; a second species P. tremuloides, 
‘quaking aspen,’’ grows on the heights. The seeds sometimes 
come down with floods and establish themselves in the valley, but 
they finally die out. 
_ The willows of the region are not very well known. They are 
mostly past flowering when botanists reach the valley and require 
special care in collecting as the male and female flowers scare 
before the leaves) are on different trees. 
_ The conifers of the valley are those common to corresponding 
elevations nearly everywhere in the central Sierra Nevada. 
Sequoia gigantea makes its nearest approach to the valley in the 
_ Tuolumne Grove seventeen miles away. 
The white cedar Libocedrus decurrens abounds on the floor of the 
valley. 
