: $26 BOTANICAL GAZETTE 
its altitude is more quickly drained, and becomes comp iratively 
dry earlier in the season. It is roughened by hummocks of | 
moss and bunch grass varying froma few inches to two feet 
high, and in circumference from that of a stove-pipe in the marsh: 
iest places to the broad, flattened, and rounded knolls of 5 
general surface. In the crevices between the hummocks, which 
may be narrow and deep or shallow and varying in breadth, li : 
streams of various sizes trickle along, working their way to the 
larger creeks. Here and there are perennial springs. Most of 
the water that flows from the tundra comes from the thawing ¢ 
the subterranean ice, and the small glaciers that remain in the 
higher valleys after the snow disappears. These endure tie 
entire season unless the summer is unusually warm. AS the st 
son advances and the ice and snow gradually isa dpe 
smaller streamlets dry up, so that in the month of Ai ; 
land is comparatively dry. More or less rain falls during 
summer. Some seasons are very rainy, as the summer of 
while that of 1900 was dry. Near the end of the month ot7 
I found ice six inches beneath the surface of the ground. 
formed the floor of a ground squirrel’s burrow which 1 
Everywhere the ground is covered with mosses, He 
prostrate plants, the mat varying in thickness from oF 
eral inches. Within the small crevices between the 3 
grow many of the small plants. The willows are 
shrubs of the region, on the tundra being from two to 
high, but along the rivers attaining a height of eight 0 
They are scattered here and there, or form thickets 48 © 
less in extent. Many species of plants find a home in 
ter of these thickets. ee 
I could make out but two or three life-zones in’ a 
That over which I collected may be bounded as follows 
south by the seacoast at Nome city; on the west b y. 
and its tributary, Glacier creek; on the east by Non 
the north by Boston and Grouse creeks, tributaries 
creek and Nome river. In the lower zone the s ve 
plants have a general distribution, an aggregation 
