62: SILVA OF NORTH AMERICA. BETULACEZ. 
rounded lobes shorter than the four stamens. The pistillate aments are produced in elongated panicles, 
and are inclosed during the winter in buds formed the previous summer in the axils of the leaves of 
short lateral branchlets, and are long-pedunculate and about a third of an inch long and a sixteenth of 
an inch thick. The strobiles are raised on slender peduncles, and are borne in elongated sometimes 
leafy panicles from four to six inches in length ; they are oblong and from one half to five eighths of 
an inch in length and about one third of an inch in thickness, with truncate scales thickened at the 
The nuts are oval, and about as wide as their thin wings. 
Alnus Sitchensis is distributed along the northwest coast of North America from the borders of 
the Arctic Circle to Oregon ; it is common in the valley of the Yukon, and ranges eastward through 
British Columbia to Alberta, and through Washington and Oregon to the western slopes of the 
Rocky Mountains. At the north, mingling with dwarf Willows, it forms great thickets,' and in 
southeastern Alaska it often becomes a tall slender tree on the rich moist bottom-lands near the 
apex. 
mouths of mountain streams, or, ascending nearly to the limit of tree-growth, at high elevations is 
reduced to a low shrub. In the valley of the Yukon it is very abundant on the wet banks of streams, 
where it is often arborescent in habit,’ and in British Columbia® and the United States it is generally 
small, growing usually only at elevations of more than three thousand feet above the level of the 
sea, and often forming thickets on the banks of streams and lakes.* 
Alnus Sitchensis, which was long confounded with Alnus Alnobetula, the Green Alder of the 
northeastern states and Europe, was found in 1827 on Baranoff Island in the neighborhood of the 
town of Sitka > by K. H. Mertens.® 
Idaho. 
1 Seemann, Bot. Voy. Herald, 17, 41. See, also, Dall, Alaska and 
its Resources, 440. 
In the Gray Herbarium there are specimens of Alnus Sitchensis 
collected by John Muir at St. Michael on Norton Sound in 1881, 
and by M. W. Hasseyter on Popoff Island, one of the Shumagin 
group, in 1872. 
2 Gorman, in litt. 
8 Alnus Sitchensis was collected by Dr. George M. Dawson in 
1876 on the Iltasyonco branch of the upper Fraser River. It has 
also been collected by J. Macoun at Hector in the Rocky Moun- 
tains, at Lake Louise, and on Rogers Pass near Glacier, on the 
line of the Canadian Pacific Railroad, and on Crow Mountain Pass, 
Alberta. 
4 In 1883 Alnus Sitchensis was collected by W. M. Canby and 
C.S. Sargent near the head of the Jocko River in Montana, and 
in 1892 by J. H. Sandberg on Cedar Mountain, Lahat County, 
In 1880 I found this Alder on Silver Peak near Yale, 
British Columbia, at elevations of forty-five hundred feet above the 
sea, and also on the banks of the Fraser in the same region. These 
specimens were after referred to Alnus tenuifolia, Nuttall, which 
In 1896 I found it on the banks of 
the Soldue River among the Olympic Mountains of Washington, 
does not approach the coast. 
on Mt. Hood, Oregon, at high elevations, on the Blue Mountains 
of eastern Washington,where it is very abundant, and on the shores 
of Avalanche Lake, Montana, at an elevation of four thousand feet 
above the sea-level. 
5 It is probable that Dr. John Richardson was the discoverer of 
this species during his journey with Captain John Franklin to the 
shores of the polar sea of North America during the years 1819- 
22, (See Franklin, Jour, Appx. No. 374, as Alnus glandulosa.) 
6 See xii. 80. 
EXPLANATION OF THE PLATE. 
Prarr DCCXXVII. Anus Srronensis. 
1. A flowering branch, natural size. 
oe ae 
A nut, enlarged. 
A staminate flower, enlarged. 
A pistillate flower, enlarged. 
A fruiting branch, natural size. 
A fruit-scale with its nuts, enlarged. 
A leaf, natural size. 
