The Scottish Flora. 13 



wood our difficulties begin. Tlie botanical survey of this country 

 owes its initiation and its ground plan to the late Dr Robert 

 Smith, whose untimely death was a very heavy blow to British 

 science. He himself surveyed Edinburghshire and North Perth- 

 shire. His brother, W. G. Smith, carried out the survey of Forfar 

 and Fife, and in collaboration with Rankin that of Yorkshire ; 

 whilst Dr Lewis has surveyed the Eden, Wear, and Tyne valleys, 

 and Moss has studied part of the Pennines. 



The present height to which the birch, pine, and oak ascend 

 is given b)- all these authors, and may be roughly placed as 

 follows : — 



The upper limit of the oak lies between 750 ft. and 1250 ft. 



That of the Scotch pine „ 1250 ft. and 2400 ft. 



That of birch „ 1250 ft. and 2750 ft. 



So that one may say that, so far as this information goes, it seems 

 that the birch came first, then the Scotch pine, and finally the 

 oak. At the same time the records are not conclusive in show- 

 ing that a birch vegetation is a necessary preliminary to the 

 Scotch pine forest. 



But of course, as we all know, our southern uplands and 

 most of the Highlands are not covered by forest of any sort. 

 Enormous areas of Scotland consist of desolate whaup-haunted 

 moorlands or black peat haggs of the most forbidding character. 

 In the botanical survey maps we find below the Arctic alpine 

 flora, or the summit flora which corresponds to it in lower hills, 

 four different associations, which cover almost the whole country 

 from those high levels until well down in what used to be pine 

 forest or oak wood. These are grass heath, heather moor, 

 cottongrass swamp and sphagnum moor. 



These four associations are mixed and intricately confused 

 one with another. The sphagnum is a peatmoss or flow of the 

 wettest and worst description. The grass heath is dry, and with 

 ■very little peat. The heather moor is drier than the cottongrass, 

 whi(-h is not so wet or quagmirish as the peatmoss. The grass 

 heath, on the other hand, is a coarse, grassy pasture, most usually 

 of nardus, sheep's fescue, molinia or aira flexuosa. The peat is 

 very shallow or absent, and there is very little or usually no 

 sphagnum at all. Mosses of sorts can generally be found on 

 close examination about the roots of the grasses ; but they are 



