14 
NATURE NOTES. 
Alpine dwarfs. — The most simple and least unexpected 
effect of altitude is dwarfing. Want of nutriment, cold, 
and the general climatic conditions of a mountain summit 
are such as one might naturally expect to cause dwarfing. 
Strong winds, also, may have their influence, and those plants 
which do not too boldly raise their head to the blast will, 
perchance, less easily be cut off before the ripening of their seed. 
Presently we shall see that the short alpine summer is 
another, and, perhaps, very strong reason for the existence of 
dwarfs on mountain-tops. 
Examples of dwarfs. — All the examples given in this paper will 
be taken from the Rocky Mountains ; the reader who has 
travelled in Switzerland will call to mind similar instances in 
the Alps. In Coulter’s Manual of Rocky Mountain Botany, 
thirty-nine varieties are described, which are peculiar, in part 
at least, for their dwarfed stature. Such are Draba alpina, 
variety glaciaiis, a whitlow-grass from the Yellowstone region; 
Nasturtium obtusum, variety alpinum, a cress of the Uinta 
mountains; Stellaria longipes, variety Edwardsii, “branches an 
inch or two high,” mountains of Colorado, and so forth- 
reduced alpine forms. 
This dwarfing is not confined to herbaceous plants. The 
“ Quaking Asp,” Populus trcmuloides, is a tree 20 to 50 feet 
high, common on the mountain slopes of Colorado. Near 
Brush Creek, above 10,000 feet, I found the tree represented 
by a new form minor, only 6 to 10 feet high.* 
The tendency of dwarfing to be inherited.— That such dwarfing 
as I have described above is the result of external conditions 
can hardly be disputed. But does it tend to become per- 
manent ? 
Phlox is a genus of fine herbaceous plants ; Silene, in its 
usual forms, is not insignificant in size. But on the summits 
of the Colorado mountains we get species of these genera, Phlox 
ccespitosa and Silene acaulis, so dwarfed, and densely matted on 
the ground that people call them “ flowering mosses.” Here, 
clearly, the dwarfing has become permanent and peculiar to 
the species. 
Similarly, oaks in most parts of the world where they grow 
are fine trees ; in Colorado the native oak, Quercus undulata, is, 
most commonly, only a bush clothing the slopes of the 
mountains. 
The flowers do not become dwarfed .+ — The low stature, but bright 
and large flowers of high mountains are familiar to alpine 
travellers. The Polemoniums, Phloxes, Gentians, and others 
have large flowers, at least in comparison to the size of the plant. 
* Populus trevvuloides f. nov. minor , 6 to 10 feet high ; stems branching from 
the base upwards ; leaves small ; petioles red. Gulch above Micawbcr Mine, 
Custer Co., Colorado. 
f This refers to entomophilous plants ; there is a class of exceptions to be 
explained later on. 
