6o ALPINE FLOWERS AND ROCK GARDENS. 



total number of British Alpines depends on the system 

 of classification followed by the counter ; if he adopts 

 that of Bentham's " Handbook of the British Flora " 

 it will run to a hundred or so ; if he adopts that of 

 the '' London Catalogue of British Plants/' the divisions 

 of some genera like Ruhus^ Rosa, Salix^ and especially 

 Hier actum will considerably increase the number. 

 Indeed, the botanist who seeks to puzzle out the hundred 

 species of hawkweed which " The London Catalogue " 

 enumerates — to say nothing of the dozens of varieties — 

 is apt to say that there is a different Hieracium for each 

 highland mountain. Many of the plants have a wide 

 distribution, and above an altitude of 2,500 feet, 

 they form the chief vegetation of the mountain side. 

 One by one they disappear as the summits of the highest 

 hills are reached, till there are less than a dozen above 

 the 4,000 feet line. Mr. Hewitt Watson has enumerated 

 the species seen on Ben-mac-dhu and on Ben-na- 

 Bourd — two of the highest highland mountains ; 

 and he records that six species only were growing on 

 the summit of the former, — viz., the Mossy Campion 

 (Silene acaulis), the Dwarf Willow (Salix herbacea), 

 two rushes, Luzula arcuata and Luzula spicata ; one 

 Carex^ C. rigida ; and one grass, Festuca vivipara. Some 

 idea of the relative altitude attained by other plants 

 may be gathered from another list which records the 

 Ling {Calluna vulgaris)^ at a height of 2,690 feet ; the 

 Juniper (Juniperus communis), 2,660 feet; the Cross- 

 leaved Heath {Erica tetralix), 2,370 feet ; and the Sweet 

 Gale, at 1,400 feet. Here it will be noticed that some of 

 the plants, abundant on the moors, and at times found 



