228 TRANSACTIONS, NATURAL HISTORT SOCIETY OF GLASGOW. 



inclined to conclude that there was some deep-seated affinity 

 between them. But, just as we find Eryngium maritimum a 

 purely silica plant, growing, and to all appearances, thriving in 

 heavy soil without the influence of the sea, so it is with the alpine 

 plants, given the necessary conditions as to the situation and 

 moisture. Let it be granted that certain plants require certain 

 constituents for the building up of their tissues, and these they 

 extract from the decomposing rocks. Were we to assert that the 

 component parts for certain plants can only be got from 

 decomposing phylite schists, then it follows that when there are 

 no such rocks we could not expect to find such plants, and also 

 that where such rocks exist such plants should be found freely 

 distributed. This, it is well known, is not the case. Alpine 

 plants are as local as littoral plants are, consequently we have 

 rare and common alpine plants. 



Take Ben Lawers and Beinn Laoigh, the mountains fonning 

 the extreme ends of this schistose belt which we are discussing. 

 We find that there are seven of our rare alpine plants on Ben 

 Lawers that are not found on Beinn Laoigh. and five on Beinn 

 Laoigh that do not occur on Ben Lawers. Again, although all 

 the alpine region of Ben Lawers is on the phylite schists that is 

 not the case with Beinn Laoigh ; we note some alpine plants on 

 the mica schist that are not found on the phylite schist. 



Some parts of the phylites are very barren owing to the lack of 

 moisture, and some parts of the mica schists are very rich owing to 

 abundant moisture and shelter. In the corrie of Beinn Laoigh 

 above the phylites we find several arctic alpine species, and Arahis 

 petraea, a typical arctic plant, is found all over the mountain, on 

 the phylite, mica, and black schists, and on the basaltic and 

 dioritic outcrops, here and on the islands of Mull and Skye, and 

 although in other nineteen Watsonian Vice Counties it has not 

 been observed further east on the phylite belt. Then if we go to 

 Beinn Heasgarnich we find Ca/rex ustulata on the black schist, 

 and not on the phylite schist. It is well known that the range of 

 mountains under review is all more or less schistose, and all the 

 other outcropping rocks are so limited in extent that the 

 decomposing schists would probably annul any efiects they might 

 have on the flora. Before comparing the flora of these rock 

 formations with that of other rock formations, let us look a little 



