XVI FLORA ORCADENSIS. 
differences and variations, and the destruction of 
those which are injurious, I have called ‘ Natural 
Selection, or the Survival of the Fittest. ” 
Now if we take Jasione montana, or sheep’s-bit, 
as we find it in Eday, North Ronaldshay, and Fair 
Isle, we shall see that Natural Selection is fitting 
it to develop, in time, a new variety. Here are 
three islands so remote from one another that if 
some characteristic, such as inereased hairiness, were 
developed in one island it would diffuse its properties 
among the individual plants of that island; but no 
communication with the other islands, either by 
wind, waves, or insects 1s possible, owing to the 
swift currents intervening. We find, as indicated in 
the plant list under this particular plant, two peculi- 
arities that through time will no doubt develop into 
varieties. Then there is Primula scotica, isolated 
into little patches here and there throughout the 
Orkneys. One day, while wandering through St. 
Andrews, I found a specimen which differed so much 
from others of its kindred that I hardly knew it. 
Growing on a small brae composed of nothing but 
black, soft peat, it had unusually developed flower- 
stalks, elongated petioles, and narrow leaves. The 
difference from the type I at once set down to its 
peaty habitat. Some time after, in the same neigh- 
bourhood, I found some Promula in a stiff clay, 
bearine the same characteristics. This no doubt 
revealed a transition stage, owmeg to environment. 
It had travelled one stage on its way to a new 
variety of plant. One interesting feature of plant 
life is noticeable in North Ronaldshay. This island 
