2SO Scottish Mountain Plants. [Sess. 



towards the top of the spikes, while bulbils occupy the lower 

 portion. Each bulbil, readily detached from the stem, is 

 capable of becoming an independent plant. A rarer plant, 

 Saxifraga cernua, seldom flowers in its Scottish station, and 

 increases by little bulbils in the axils of the leaves, which 

 become detached and sow themselves around the older plant. 

 S. stellaris is not infrequently viviparous in Norway. Among 

 grasses, viviparity is not uncommon, Aira ceespitosa, Poa 

 alpina, and Festuca ovina being found in this condition in 

 the Highlands. 



Mountain Plants : Prominent Groups. 



The principal features, at least, of mountain floras are 

 usually well distinguished from lowland ones ; and apart 

 from the mountain flora, the country surrounding the base 

 of mountains has often a distinct character in its vegetation, 

 different from the outlying district. The mountain presence 

 often ensures a more abundant rainfall and a more regular 

 amount of surface moisture, which is favourable to the growth 

 of trees and to the plants that are associated with forests. The 

 ground at the foot of many mountains is often largely made 

 up of marsh or bog, owing to the copious supply of water 

 draining from the mountain slopes. 



The vegetation of mountains will be found to vary much. 

 Where hard rock prevails (as in Skye, &c.), the plants are 

 very few, owing to insufficient rooting material ; while on 

 crumbling micaceous slopes and cliffs, as in Breadalbane, the 

 vegetation is plentiful. Then the amount of atmospheric 

 moisture present influences the vertical range of plants. To 

 the moist climate of Ireland must be attributed the low eleva- 

 tion — often at sea-level — to which alpine plants descend in 

 that island. Many Highland plants occur in Ireland at a 

 much lower altitude. To a less degree the same occurs in 

 the extreme ISTorthern counties of Scotland, &c. In Skye, 

 Alchemilla alpina descends to sea-level. 



A great many observations have been taken in order to 

 deal with this vertical range of alpine and other plants. 

 The principal records are given in the ' Cybele Britannica.' 

 In this work, by the late Mr Watson, the zones given that 



