188 Part II. Chapter 2. 
present time. In the former place the vegetation is sparse and of the tundra 
type’), in the latter, the forest occurs on the stagnant ice margin, for the forest 
covering the greater part of the lowlands near the Malaspina Glacier at the 
base of Mt. St. Elias extends up over the moraine and thence over the sur- 
face of the glacier covered with morainic material for four or five miles ?). 
The vegetation, thus found on the glacier itself, consists principally of alders 
(Alnus oregana) growing to a height of 20 to 30 feet, but on the outer or 
older portion of the moraine, there are dense groves of spruces (Picea sitchensis), 
mixed with cottonwood (Popwlus balsamifera) and an undergrowth of salmon- 
berry (Rubus spectabilis), devil’s club Fatsia (Echinopanax) horrida, ferns and 
huckleberry bushes (Vaccinium ovalifolium?). It would appear that the glaciers 
would not affect the tree distribution at any great distance from the ice front. 
Before considering this point in detail, let us describe the tundra and bog 
conditions of these times, because, such associations of species as one finds 
in the bogs and tundra of today occupied the strip of country between the 
edge of the ice sheet on the one hand and the northern edge of the forest 
vegetation on the other. 
Since bog associations of plants may occupy under favorable conditions 
other habitats than undrained depressions, they probably existed on the borders 
of the heavily loaded streams, in ravines and moist situations generally along 
the ice front. It is to be noted, that practically all of the existing small lake 
areas of the northern states were covered by the ice during the maximum 
extension of the Wisconsin ice sheet. As there is no reason to believe that 
the drift sheets of the preceding epochs, which in many places extend beyond 
the Wisconsin terminal moraine, contained such small undrained depressions, 
it follows that the bog societies must have occupied the habitats. 
Many glacial plants other than bog plants, such as Sülene acaulıs, Dia- 
pensia lapponica, Oxyria digyna, Loiseleuria procumbens, etc. occupied dry 
land situations on the moraines, on the exposed and worn rock boulders°), Of 
in the sand along the edge of the streams, that rushed out beneath the glacial 
ice. Many of these plants, however, survived in the glacial covered country, 
as is evidenced by the fact, that flowering plants of many species have been 
collected in the short arctic summer, as far north, as the land areas of North 
1). TRAnsEAU, E. N.: On the geographical distribution and ecological Relations of the bog 
plant Societies of North America. Botanical Gazette XXXVI: 401—420 Dec. 1903; JEROSCH, 
MARIE Ch.: Geschichte und Herkunft der Schweizerischen Alpenflora. 1903, pp. 31575 Core 
MAN, A. P.: Glacial and interglacial Beds near Toronto. Journ. Geol. IX: 285: 1901; PENHALLOW, 
D.P.: The pleistocene Flora of the Don Valley, Report British Association Advancement Science 
1900: 334- 
2) RuSSELL, I. C.: Thirteenth Annual Report U, S. Geological Survey 1891— 1892, pp- 1921; 
Glaciers of North America. 1901. 
3) See Fig. ı of plate II: Diapensia lapponica on the top of the Adirondacks, Mt. Tahawus 
1630 m. — Fig. 2 shows in Cornus canadensis a subglacial type occupying the uppermost forest 
region, 
