IN ASCENDING REGIONS. 69 



though not always exact. In Cumberland, the Calluna is 

 rarely seen above the median region, the highest point at 

 which I observed it being little more than 800 yds; a 

 height rather exceeded by Pyrus Aucuparia and Juni- 

 perus communis (nana). On the Grampians, the true 

 limit of Calluna appears to be at about 1000 yds. I have 

 seen it at 1050 yds on the Cairngorm mountains, and in 

 several places above 900 yds. On the Nevis range it 

 ceases at 700 to 850 yds, according to aspect and moisture. 

 On Ben Hope in Sutherland it ascends to 800 yds ; and 

 to 750 yds on Ben Loyal, in the same county. About 

 950 yds may be guessed as an average for latitude 56° — 

 57°, and 750 yds for 58° — 59° ; or perhaps a little more. 

 Very few species are peculiar to this region. Draba 

 rupestris, Saxifraga cernua, S. rivularis, and Luzula 

 arcuata are so ; possibly also Stellaria cerastoides and 

 Arenaria rubella. The other species, commonly called 

 alpines, descend more or less to the subalps, though for 

 the most part about streams or among rocks. Here, 

 however, they form a large constituent of the scanty sward 

 round the mountain summits ; while the few species of 

 the plains straggling thus high are usually very weak and 

 stunted. Luzula spicata, Silene acaulis, Carex rigida, 

 Festuca ovina (yivipara) and Salix herbacea occupy the 

 highest summits in abundance ; and, nearly as high, occur 

 Saxifraga stellaris, Gnaphalium supinum, Statice Armeria, 

 Juncus trifidus, Alchemilla alpina and Sibbaldia procum- 

 bens, commonly in great plenty. Leontodon Taraxacum 

 (palustre) and Rumex Acetosa ascend to a great elevation 

 but seldom produce flowers above the limit of Vaccinium 

 Myrtillus. The whole vegetation is remarkably dwarfed. 

 The species found on the alps are those of small size at 

 their fullest expansion, and here they are most of them 

 much smaller than at lower elevations, and in more 

 sheltered places. Vaccinium Myrtillus and Empetrum 



