NATURAL HISTORY SOCIETY OF GLASGOW. 17 



tridadylus). He likewise laid ou the table the eggs of the 

 purple sandpiper, avocet, turnstone, black tern, BaLllon's crake, 

 and little owl. 



PAPER READ. 



On the Distribution of the Vascular Plants of Britain, more particularly 

 those of the East and West of Scotland. By Mr James Rajvisay. 



I fear the following remarks, which are more suggestive than 

 instructive, will prove anything but interesting, as I have confined 

 myself almost entirely to an enumeration of facts, for the simple 

 reason, that I find myself wholly unable to account satisfactorily 

 for the distribution of the majority of the species I have mentioned. 



The physical laws that regulate the distribution of plants over 



such a limited area as that of the British Islands, are in many 



instances easily understood, but they are as frequently involved 



in great obscurity. Observation has taught us that plants will 



increase only when growing under conditions that are favourable 



to them; and when these conditions are local in their character, 



they account in a satisfactory manner for the extremely limited 



distribution of some species. The character of the vegetation on 



the lofty range of the Grampians, compared with that of the 



fertile valleys of the lowlands, is not greater than we might 



reasonably expect, and the mind is satisfied that elevation and 



other concomitant circumstances sufiiciently account for all the 



diff'erences existing in the natural productions of localities marked 



with such strong features of contrast. The variety of climate, 



resulting from the few degrees of latitude that intervene between 



the northern and southern extremities of our island, also afford a 



satisfactory solution of the problem why certain species are found 



in the north and not in the south, and vice versa. But besides 



these there are a good many species confined to one or a few 



localities at most, the unequal distribution of which cannot always 



be satisfactorily accounted for, either by difference of soil, climate, 



elevation, or exposure. The number of species that abound in 



East Lothian, for instance, and rarely, if at all, to be met with in 



Ayrshire, is very great, if we consider how closely the one locality 



resembles the other in most of the conditions that Ave would 



suppose necessary to the production of a similarity of vegetation. 



Climate appears to be the most powerful, if not the only influence, 



in determining the habitat of such plants as SlUhorpla Euroepea, 



C 



