Rocky Mountain maple, also called dwarf maple 1 and sometimes known as 

 mountain maple and rock maple, varies in size from a bush about 7 feet high 

 to a small tree. It is one of the most widespread maples on the western 

 ranges, being distributed from South Dakota and Montana to Idaho, Oregon, 

 California, and New Mexico. As the common name indicates, this plant is 

 essentially a Rocky Mountain rather than a Pacific species. It is largely 

 replaced in the Northwest by Douglas maple (A. douylasii, syn. A. glabrum 

 doufflasii). Although these two species are often merged by botanists, typical 

 s-pecimens of each are readily distinguishable, and the best present-day 

 botanical opinion is that they are separate species. Two forms of Rocky 

 Mountain maple have been described as separate species (A. neo-mexicanmn 

 and A. tripartitum) , on the basis of their three-parted leaves, but the three- 

 foliate leaf character is not constant, since both compound and simple leaves 

 are often found on the same plants. .Most authorities now agree that these 

 variants do not merit specific rank. 



Rocky Mountain maple grows on mountain slopes, along streams, moist 

 canyons and gulches, and in moist flats among timber, such as open Douglas 

 fir, aspen, western larch, red fir, and ponderosa pine. It is most characteristic 

 of porous, sandy or gravelly loams, but also appears on cliffs and rocky can- 

 yon sides or on dry brushy sites, frequently associated with serviceberry, 

 chokecherry, spirea, and snowberry. Although it thrives best at moderate 

 elevations, it extends from the foothills to altitudes of over 10,000 feet in the 

 southern part of its range. This plant usually appears as a dense low shrub 

 growing as scattered individual clumps, but occasionally occurring in abun- 

 dance as one of the dominant shrubs on localized range areas. In the most 

 favorable sites it sometimes assumes tree-like proportions, reaching heights 

 of 20 to 30 feet, with a short trunk 6 to 12 inches in diameter. 2 



The forage value of Rocky Mountain maple varies from practically worthless 

 to good. In eastern Montana, Wyoming, Colorado, Utah, much of the Great 

 Basin region and the Southwest, it is considered worthless or poor for all 

 classes of livestock. However, it ranks as fair for sheep and goats and poor 

 for cattle in western Montana, northern Idaho, and parts of Oregon, and is 

 rated fair to good for sheep and fair for cattle in California. Game animals 

 apparently utilize the herbage of this maple extensively. Dixon * found that the 

 leaves, twigs, and sprouts are fair in palatability for mule deer in California. 



The foliage and twigs of this maple are smooth and mostly hairless (glabrous), hence 

 the specific name ylabrum. The graceful shining foliage contrasts beautifully with the 

 often red petioles and branches. The leaves are often- infested by a blight or fungus 

 which causes portions of the leaves to turn a bright red during the growing season. 



DOUGLAS MAPLE (A. dougla'sii, syn. A. gla'brum dougla'sii) 



Douglas maple, known also as mountain maple or dwarf maple, is a shrub or 

 small tree, very similar in many respects to Rocky Mountain maple. These two 

 species can usually be distinguished by their leaf characters. Douglas maple 

 leaves have 3 to 5 taper-pointed, sharply toothed lobes, the sinuses between the 

 lobes are usually shallow and open, and the lobes are toothed all the way to the 

 base ; the wings of the "seeds" of Douglas maple are incurved on the back, and 

 the sinuses between the wings are rounded. In contrast, the leaves of Rocky 

 Mountain maple are rounder in outline, with the three to five lobes usually 

 broader or more obtuse toward the apex. 



Douglas maple is essentially a Northwestern species, distributed from Alaska to Van- 

 couver Island, Washington, and Oregon, and extending eastward through the Blue Moun- 

 tains of Oregon to northwestern Wyoming and Alberta. It is often common on brushy or 

 timber-covered slopes, in fairly heavy shade, about seeps and springs, and along streams, 

 at elevations ranging from sea level to about 6,000 feet. It attains its best development 

 in rich moist loams, where it occasionally grows to tree size, reaching a height of 40 feet 

 and a diameter of from 12 to 18 inches. This plant commemorates David Douglas, the 

 famous Scotch botanical explorer, who discovered this Kpecies. 



The palatability of Douglas maple is usually fair for cattle and fair to good for sheep 

 and goats. Deer and elk eat freely of the leaves, especially in the spring and early sum- 

 mer, and browse the twigs in the fall and winter. 



1 Sudworth G B. CHECK LIST OF THE FOKEST TREES OF THE UNITED STATES, THEIR 

 NAMES AND RANGES. U. S. Dept. Agr. Misc. Circ. 92, 295 pp. 1927. 



2 Sargent, C. S. MANUAL OF THE TUBES OF NORTH AMERICA (EXCLUSIVE OF MEXICO). 

 Ed. 2, reprinted with corrections, 910 pp., illus. Boston and New York. 1926. 



3 Dixon J S A STUDY OF THE LIFE HISTORY AND FOOD HABITS OF MULE DEER IN CALI- 

 FOBNIA. PART 2. FOOD HABITS. Calif. Fish and Qame 20(4) : [315] -354, illus. 1934, 



