98 MISC. PUBLICATION 101, U. S. DEPT. OF AGRICULTURE 
Mortonia, a genus of three species, all low bushes with small — 
remarkably thick leaves, is found at low elevations, often in lime- — 
stone sites. el 
Myrtle boxleaf (Pachistima®? myrsinites), known also as box- 
wood, false box, goatbrush, mountain lover, and myrtlebush, is a 
low, prostrate shrub, with thick evergreen leaves (pl. 7, A), ranging 
from British Columbia to California, New Mexico, and Alberta, and 
occurring in mountain woods mainly in the yellow pine-Douglas fir 
and Engelmann spruce zones. In the Northwest it grows mainly 
at altitudes between 2,000 and 4,500 feet and in the Great Basin, 
Colorado, and northern Arizona and New Mexico between 6,009 and 
9,000 feet. It is characteristic mainly of moist or fairly moist sandy 
or gravelly loams in cool open conifer woods, but is not infrequently 
encountered in drier sites and grows on all slopes. 
Myrtle boxleaf is important chiefly because of its abundance and 
wide distribution; it is usually unpalatable to livestock. Occasion- 
ally it is observed to be materially browsed by sheep or cattle, 
ordinarily, however, where palatable feed is scarce. Lenzie reports 
that myrtle boxleaf is not eaten in west-central Washington unless 
desirable forage is absent (as along driveways), but that sickness 
ensues when it is browsed to a considerable degree. Ingram reports 
the local repute of myrtle boxleaf in southwestern Oregon as a 
remedy for kidney and rheumatic disorders. The chemical proper- 
ties of this species would probably repay study. 
MAPLE FAMILY (ACERACEAE) 
MAPLES (ACER SPP.) 
The genus Acer is a large one, the United States ordinarily be- 
ing credited with about 26 species, including the boxelders, often 
called ashleaf maples (Wegundo spp.). Of these about 10 or 11 
species are western. In the East, maples are of great importance in 
the lumber trade, but most of the western species are smaller and 
outside of bigleaf maple (A. macrophyllum) have little, if any, 
significance in the lumber trade nor in any industry comparable to 
the maple-sugar industry associated with sugar maple (A. sacchar- 
um). A number of the western maples furnish at least fairly pala- 
table browse in good quantity and shade for livestock and game 
animals during the heat of the day. 
Rocky Mountain maple (Acer glabrum, syn. A. neomexicanum) 
(fig. 26), also called dwarf maple (131) and sometimes known as 
mountain maple and rock maple, varies in size from a bush about 
7 feet high to a small tree. It ranges from South Dakota to Idaho, 
Oregon, California, and New Mexico, but is probably rare in Oregon 
and California. Essentially a Rocky Mountain rather than Pacific 
species, it is replaced westward by A. douglasti, syn. A. glabrum 
douglas, with which it is often confused in the floras. Rocky | 
Mountain maple often occurs in limestone areas and grows on slopes, 
in canyons, along streams, and in moist flats among timber, such as 
~The spelling is the original one and is the form approved by the American Joint Com- 
mittee on Horticultural Nomenclature (3) for both the Latin and vernacular name. How- 
eyes ae spelling Pachystima adopted by some authors is more in accord with the 
etymology. 
