102 MISC. PUBLICATION 101, U. 8. DEPT. OF AGRICULTURE 
slopes, sometimes in pure stand in bottom lands, but usually as 
an understory in conifer forests. In Washington and Oregon it 
extends to an altitude of 3,500 feet; in the Sierra Nevada it occurs 
between 2,000 and 5,000 feet. a 
Although bigleaf maple has the largest leaves among the maples 
all, or nearly all, the leaves of the maturer trees are usually out of 
reach of grazing animals. When the foliage is within reach it 
is cropped with fairly good or good relish by cattle and horses and 
is of fair to poor palatability for sheep. 
Boxelders (section Negundo, syn. Rulac) 
The boxelders, often called ashleaf maples, held by some authors 
as generically distinct from the true maples, are represented in the 
West by perhaps six species or varieties, termed by a number of 
authorities varieties of the eastern A. negundo. Probably the most 
familiar of these are inland boxelder (A. interiws, syn. A. negundo 
intertus) (fig. 27) ranging from Manitoba to Nebraska, and Arizona, 
and California boxelder (A. californicum, syn. A. negundo califor- 
nicum) in California. Boxelders are found in moist places along 
streams in mountain canyons and the lke, but are as a rule too 
rare and local, and often too large, to figure in the carrying capacity 
of the ranges, although their palatability is sometimes rated as 
ood. 
Z SOAPBERRY FAMILY (SAPINDACEAE) 
The -horsechestnut-buckeye group (Aesculus and Ungnadia) are 
placed by some botanists in a distinct family, Aesculaceae, or Hippo- 
castanaceae. 
California buckeye (Aesculus californica) (pl. 7, B) occurs both 
as a bushy shrub and asa small tree. It is confined to California and 
is the only genuinely western representative of its genus. It is essen- 
tially a cove species and reaches its largest size in moist mountain 
valley lands of moderate or low elevation, but is not infrequently met 
with in drier sites in the foothills, mostly in drainage basins subject 
to subirrigation. 
Both the fruit and leaves of California buckeye are reputed by 
stockmen to be poisonous, and there seems to be no question but that 
it should be listed as a poisonous species (/7, 66). Chesnut (78) 
states that the fruit is “a favorite food for squirrels, but hogs will 
not eat it.” Vansell (737) reports losses and disease, sometimes very 
severe, among California honeybees and their larvae from the effects __ 
of the nectar, pollen, and sap of this species. 
Hopbush (Dodonaea viscosa angustifolia,* syns. D. angustifolia, 
D. schiedeana) (fig. 28) is a cosmopolitan shrub or small tree 
found in the warmer parts of both hemispheres, but reported in 
the United States thus far only from Arizona and peninsular 
Florida. In Arizona it is mostly a bush 3 to 6 feet high. Wind 
and birds as agents in seed dissemination presumably account for the 
remarkably wide distribution of the bush, a distribution which few 
woody plants can equal. The shrub is fairly common in southern 
28 Some botanists do not recognize the variety angustifolia, but merge it wholly in the 
species D. viscosa. Some authors pldce Dodonaea in a family of its own, Dodonaeaceae. 
