8 BULLETIN UNITED STATES GEOLOGICAL SURVEY. \rol.TI. 



of these are known to extend to Arctic America. Of the whole 111 

 species about 50 are not known in Europe and Asia in identical species. 



The list of Eocky Mountain alpine species reaches the number of 184. 



Those of the Sierra in California, and northward up to the British 

 boundary, to 111. 



Those of the mountains in the northeastern part of the Atlantic States 

 (the Alleghanies, though reaching a greater altitude, are not high enough 

 for the latitude to have any alpine vegetation, though they verge on it) 

 are only 52. 



The comparative meagerness of this last list is not surprising when 

 we consider how very restricted the alpine area altogether is in Maine, 

 New Hampshire (which has most of it), and the northeastern corner of 

 New York. And we have not taken into account the arctic-alpine spe- 

 cies which descend to the sea-level on the shores of the Gulf of Saint 

 Lawrence, nor the few which occur on the bleak northern shore of Lake 

 Superior. The latter, as some one has well suggested, owe their exist- 

 ence or continuance there neither to the absolute elevation nor to the 

 latitude, but to the moist bleakness of a wind-swept coast, which gives 

 them congenial summer conditions, on ground which forest cannot stand 

 upon, owing to the severe exposure. Yet this forest resumes its sway 

 northward, as soon as some shelter is given. 



The Pacific alpine region, notwithstanding its long stretch along the 

 mountain tops of a continuous but narrow north and south range, is 

 also a restricted one. In California only the very culminations of the 

 Sierra Nevada can be said to be alpine, and they are too arid in summer 

 for the development of a true alpine flora. In Oregon and Washing- 

 ton Territory there is equal height under more northern parallels of 

 latitude, abiding snow, and summer rain. The botany of these heights 

 is far from weU known. Probably all the arctic species of the Eocky 

 Mountain column also belong there, and a fair share of exclusive 

 species. 



It is difficult to say what are or are not alpine species in the Sierra 

 Nevada, especially southward, where, notwithstanding the heavy winter 

 fall of snow, the higher elevations are unwooded from dryness as much 

 as from cold. But, as we have excluded species which show themselves 

 to be at home at lower altitudes, and have included all arctic-alpine 

 types, the number of questionable character is very small. 



Nor, except that we know their ranges and aptitudes better, is there 

 much less difficulty in drawing a line between truly alpine and alpes- 

 trine species in the other regions. There are a goodly number of spe- 

 cies which are normal to low altitudes or to the sea-level in the northern 

 temperate zone, such as Campanula rotundifoUa, Taraxacum Dens-leonis, 

 Androsace septentrioiialis, Uriophorum alpinum, polystachyon, &c., and 

 Festuca ovina, which also flourish in an alpine station. And, indeed, 

 these same species, and others like them (such as Erigeron compositmn, 

 which flourishes at the base as well as on the highest summits of the 

 Eocky Mountains, and also in Greenland), make a part of the extreme 



