28 TRANSACTIONS AND PROCEKDINGS OF THE [Sess. lxv. 



deer forests, as more herbage is left unconsumed Ijy deer 

 than by sheep. In the lower parts of the hills the intro- 

 duction of sheep has made a more conspicuous alteration 

 on the flora, as it was only after their introduction that 

 heatlier burning took place. AVe read of the heather in the 

 eighteenth century being as high as a man's waist, and we 

 see at the present time, when it is allowed to grow more 

 than a foot or so in height, that the underlying flowering 

 plants are choked and die, but that a great increase takes 

 place in mosses, especially in Hypnum 2nirum and Thuidium 

 tamariscinum. When large stretches of such parts of the 

 hill ground were thus covered by long heather, other 

 flowering plants, especially grasses, must have been much 

 scarcer than at the present time. By repeated burning in 

 good soil the heather in time becomes destroyed, its place 

 being taken by grass, with a mixture of other flowering 

 plants. In the memory of people living at the beginning 

 of last century, the appearance of hills familiar to them 

 had quite changed from the brown of heather to the 

 green of grass. An increase in the spread of the bracken, 

 unfortunately still going on, is a result of this burning. 

 These changes in the flora, though perhaps sometimes over- 

 looked, have had more important results than would be the 

 case by the presence or absence of some rare species. The 

 diminution of many of these rare species by botanists and 

 others during the last century is a matter of history, but 

 the range of most has been shown of late years to be wider 

 than what was previously supposed. 



A later introduction -than that of the south country 

 sheep is the rabbit, and the alteration caused by it in the 

 flora must be considerable, though not so conspicuous. In 

 the eighteenth century these animals were scattered over 

 the West Highlands, but only in small quantity. They 

 were, during the latter half of last century, introduced for 

 the sake of sport, and have now generally overrun the low- 

 lying parts. The most noticeable change in the flora which 

 they are making is the destruction of the native holly by 

 barking the stems. So much is this the case that in some 

 districts the continuation of this tree as a native is only 

 effected where seedlings have taken hold of inaccessible 

 rock ledges. This generally implies only a small amount 



