SILVA OF NORTH AMERICA. BETULACEZ, 
66 
middle and yellow below. The pistillate aments are short-stalked and about three quarters of an inch 
in length, with ovate acute green scales and bright red styles. The strobiles ripen in August and 
are cylindrical, rather obtuse, from an inch to an inch and a quarter long, and erect or pendulous on 
slender glandular petioles from one quarter to nearly three quarters of an inch in length; the scales 
are puberulous or sometimes nearly glabrous, ovate, longer than they are broad, and wedge-shaped 
below, with stout nearly erect lateral lobes. The nut is ovate or obovate and puberulous at the apex, 
with a wing much broader than the seed. 
Betula occidentalis, which grows in moist soil near the banks of streams in mountain canons, is 
widely and generally distributed, although nowhere very common, throughout the northwestern and 
central regions of the continent. From the basin of the upper Fraser and Pease Rivers in British 
Columbia it ranges southward to the valleys of Mt. Shasta and the canons on the eastern slopes of the 
northern Sierra Nevada in California, eastward through Albertina along the valley of the Saskatchewan 
to the neighborhood of Edmonton,! and southward along the Rocky Mountains and other interior 
ranges to Nevada, Utah, and northern New Mexico, spreading eastward to the Black Hills of Dakota,’ 
northwestern Nebraska,* and the eastern base of the Rocky Mountains in Colorado. 
The wood of Betula occidentalis is soft and strong, although brittle, and close-grained ; it is light 
brown, with thick lighter colored sapwood, and contains numerous obscure medullary rays. The specific 
gravity of the absolutely dry wood is 0.6030, a cubic foot weighing 37.58 pounds. It is sometimes 
used for fuel and for fencing. 
Betula occidentalis, which enlivens sombre cafions and elevated valleys with its masses of graceful 
feathery stems, its beautiful lustrous bark and the cheerful green of its foliage, was discovered by 
Lewis and Clark on August 5, 1805, on the banks of the Jefferson River at the eastern base of the 
Rocky Mountains ; * and afterwards was found by Dr. John Scouler ° near the coast of British Columbia. 
In 1874 Betula occidentalis was introduced into the Arnold Arboretum, where, as a small shrub, 
it flowers and ripens its fruit. 
1G. M. Dawson, Can. Nat. n. ser. ix. 331. — Macoun, Cat. Can. 
Pil. 437. 
in company with David Douglas, Madeira, Brazil, and the north- 
west coast of North America, where he remained from 1825 to 1827 
2 Williams, Bull. No. 43, South Dakota Agric. Coll. 108. 
8 Bessey, Rep. Nebraska State Board Agric. 1894, 111. 
4 History of the Expedition under the Command of Lewis and 
Clark, ed. Coues, il. 457. 
5 John Scouler (1804-71), a native of Glasgow, was graduated 
from the Medical School of his native city, and became a zodlogist 
and geologist. In 1824 he was attached to the Hudson’s Bay Com- 
pany’s ship William and Ann as surgeon and naturalist, and visited, 
and made collections of plants which he sent to his teacher of 
botany, Sir William J. Hooker, who named in his honor Scouleria, 
On his 
return from America Dr. Scouler visited India, and afterward set- 
a genus of Mosses discovered by him in North America. 
tling in Glasgow was appointed professor of natural history in the 
Andersonian University. From 1833 to 1854 Dr. Scouler was pro- 
fessor of zodlogy and botany in Trinity College, Dublin. (See 
Trans. Geolog. Soc. Glasgow, iv. 194.) 
EXPLANATION OF THE PLATE. 
Puate CCCCLIII. Beruna occipENTALIs. 
A nut, enlarged. 
CoONonr wWnw eh 
. A flowering branch, natural size. 
Scale of a staminate ament, rear view, enlarged. 
. Pistillate flowers with their scale, front view, enlarged. 
. A fruiting branch, natural size. 
. Seale of a strobile, rear view, enlarged. 
. Scale of a strobile, front view, with nut, enlarged. 
. A winter branch with staminate aments, natural size. 
. A young branchlet with unfolding leaves and stipules, natural size. 
