244 CONTRIBUTIONS FROM THE NATIONAL, HERBARIUM. 



(but no important ones) which he did not find on the west slope, 

 but it is probable that this is due to the less aniount of time spent 

 in the latter region, and to the lateness of the season at which the 

 collections were made. On the plains east of the park (Transition 

 Zone) there are many species of plants not found on the west slope, 

 because there is no similar area in the latter region. 



On both slopes of the park it is apparent that the vegetation of 

 the Canadian Zone is not homogeneous, and that there is a marked 

 difference between the lower and upper portions. On the west 

 slope the great silver fir, hemlock, western white pine, larch, giant cedar, 

 aspen, cotton wood, and canoe birch are found only at lower levels. 

 These, it may be noted, include all the Pacific coast species. The larch 

 extends higher up, perhaps, than any of the others. It is at the low 

 altitudes that the forest is most dense; higher up the timber is thinner, 

 and spruces and alpine fir are more abundant. Around Lake 

 McDonald the lodgepole pine, which is so abundant on the east slope, 

 is not very common, and its place is taken largely by the larch. 



On the east slope the lower part of the Canadian Zone is timbered 

 chiefly with lodgepole pine, which often forms extensive, dense, 

 nearly pure stands, and with aspens. There is some admixture of 

 Cottonwood, Douglas fir, and limber pine, and frequently of other 

 trees. In some places there are areas covered almost exclusively^ 

 with Douglas fir, and the aspen forms extensive groves, especially 

 along the automobile road. On the higher slopes the trees are 

 chiefly alpine fir, spruces, and Douglas fir. There is a pronounced 

 difference also in the herbaceous vegetation of the two belts of this 

 zone. 



There are numerous special localities in the Canadian Zone which 

 are of particular interest botanically. Along the streams are many 

 swampy thickets, where water-loving plants abound. Most of the 

 larger lakes lie in this zone, but their flora is rather meager. In 

 most of thern. the water seems to be too cold for the growth of water 

 plants, but in St. Mary and McDonald lakes several pondweeds 

 grow in some quantity. On the west slope there are small lakes 

 only a few acres in extent where pondweeds, yellow pondlily, 

 bur-reeds, bladdervvort, and other water plants are plentiful. In 

 slow stretches of the streams pondweeds, Callitriche, bur-reeds, 

 water buttercups, and other plants are often found. 



One of the most interesting localities in the Many Glacier region 

 is a bit of deep swampy woods along Swiftcurrent Creek, shortly 

 below the falls (see pi. 36). This area is difE.cult to explore because 

 of fallen logs, beaver dams, and bogs, but it yields many plants 

 that locally are rare, such as Cornus canadensis, Habenaria ohtusata, 

 Pyrola minor, and MiteUa nuda. Farther down the stream, close 

 to the automobile road, is a boggy meadow, in whose center rises a 



