5 



its altitude, it is characterised by a ratlier arctic form of Vegeta- 

 tion, though it contains only a very few plants which do not 

 descend into the other zones. (2). The mid-alpine or rocky 

 zone, characterised chiefly by wide corries, steep precipices, deep 

 tarns and rapid streams, stretching from the preceding to about 

 2,500 feet, and which is more or less fully represented on all our 

 higher mountain ranges. Its vegetation, unlike that of the pre- 

 ceding, is both varied and abundant, consisting chiefly of the 

 rarer and more prevailing species which constitute our 

 Alpine Flora. (3). The sub -alpine or heathy zone, char- 

 acterised chiefly by dry moors, peaty soil, wet marshes, 

 and dark lochs, reaching to the lower limit of this region, 

 and better represented than either of the others, in all 

 our mountain ranges. It contains a flora which is partly its 

 own and partly derived from the upper and the lower tracts, in 

 the alpine and the lowland regions. But here it is of importance 

 to observe that this zonal distribution is applicable not only to our 

 phsenogamics, to which it is usually limited, but also to our cryp- 

 togamics, to which it has very seldom, if ever, been applied. And 

 this, probably, for the reason that at first sight the majority of 

 the cryptogamics seem to be much less affected by such divisions of 

 elevation, though a closer and more minute inspection sufficiently 

 demonstrates that either in kind, in number, or condition, they 

 are in reality thus influenced to a very considerable, if not equal 

 degree. The Alpine floral region, then, consists of plants which 

 are found only between the above-mentioned limits of vertical 

 range in Great Britain. Some of them, however, under special 

 circumstances, such as growing in the northern maritime tracts, 

 and on more isolated and exposed peaks, or in consequence of 

 being washed down by the streams, not unfrequently occur at 

 much lower altitudes. Our native Alpine phamogamics consti- 

 tute about 1 -15th of our whole flora ; while the cryptogamics, 

 with the exception of the fungi and algaj, form a still larger pro- 

 portion of the British species. 



