STANDLEY FLORA OF GLACIER PARK. 237 



the summer there is a lavish display of color, which attains its 

 climax about the first of July. The flowers follow close upon the 

 retreating snow banks, and thus even when they are somewhat 

 faded at lower altitudes they may be seen in all their vernal 

 freshness on the high slopes. The growing season is so brief that 

 plants must bloom and fruit quickly. At high altitudes, and to 

 some extent at middle ones, there are no "spring," "sumLmer," or 

 "fall" flowers, for nearly all plants are in bloom at once, asters and 

 goldenrod mingling with violets, springbeauties, and anemones. At 

 low altitudes, however, there are marked differences between the 

 spring and autumn floras. 



The flora of Glacier Park is in general typical of the Rocky 

 Mountain region, but like that of any restricted area it shows 

 certain special characteristics. The Continental Divide, which 

 traverses the park, is to a certain extent a barrier to plant migra- 

 tion, and there are noticeable differences between the plants of the 

 east and west slopes. The differences are most conspicuous in the 

 case of the trees, and will be discussed in detail further on. In 

 general, the flora of the east slope is like that of the central Rockies, 

 while the flora of the west slope shows a marked relationship to 

 that of the northern Pacific coast. It is noteworthy that a large 

 number of coastal species reach the eastern limit of their range 

 (in the United States at least) in Glacier Park. Many char- 

 acteristic plants of the mountains of Alberta and British Columbia 

 reach their southern limit in this region, and several such plants 

 collected in Glacier Park have not been found elsewhere in the 

 United States. Of course, more thorough exploration of the 

 mountains of western Montana may show that some of these have 

 a wider range than is known at the present time. 



The forests of the park are of chief interest to those who come 

 from the East. Like all western forests, they are composed almost 

 wholly of coniferous trees belonging to a comparatively small 

 number of species. The only broad-leafed tree which occurs in 

 much abundance is the aspen. The forests of the east slope are 

 only moderately heavy, but those of the west slope, especially 

 about Lake McDonald, are very dense and are composed of large 

 trees. The forests of the west slope are similar to those of the 

 Pacific coast, although they are not so extensive or luxuriant. 



Since there is practically no cultivated land inside the park, few 

 introduced plants are to be expected, and in the present list there 

 are included only 61 species of foreign origin. Most of these have 

 been found only about Belton and the east entrance, where they 

 have become established along the railroad. A few foreign plants are 

 thoroughly naturalized in the park, however, and some are abundant, 

 such as timothy, sheep sorrel, fanweed, red, white, and alsike clover. 



