48 POPULAR GEOGRAPHY OF PLANTS. 



The vegetation of the Rocky Mountains, some portion of 

 which lies in this zone, is too vast and too difficult a sub- 

 ject for these narrow limits.* The one prevailing feature of 

 that part of those grotesque mountains is a "comparative 

 barrenness and desert-like appearance, some small parts of 

 river-valleys only excepted. The most prevalent colours 

 amongst the flowers are white and yellow ; the white colour- 

 ing is occasioned by Acliillea Millefolium ; the yellow by 

 Calliojpsis bicolor, with Helianthus tubaformis, Stanleya, 

 divers Solidagines, and Ranunculi" A plant, called Shep- 

 herdia, resembling our Sea Buckthorn (Hippopfiae), is very 

 abundant in those districts ; and a striking feature is formed 

 by the Yucca, "with its rich symmetrical, silvery foliage, 

 and floribund scapes. The colour of the foliage passes 

 through every shade, from deep dull green to silvery- white, 

 the trees being chiefly Cupwlifera and Conifers, besides 

 groves and thickets of Salicinea" 



Passing on to the forests of Canada, we find they are of 

 two distinct kinds; namely, boundless Eir-forests, and forests 

 of deciduous trees. Amongst the latter, the Maple appears 

 to predominate : they are composed, besides, of Beeches, 



* A detailed and interesting account of Geyer's Journey across the Rocky 

 Mountains, etc., is given in the ' London Journal of Botany,' vols. iv. and v. 



