Floiucrs and their Pedigrees. 



distribution over its surface has to be explained on 

 historical grounds just as a future ethnologist would 

 have to explain the occurrence of isolated French 

 communities in Lower Canada and Mauritius, of 

 African negroes in Jam.aica and Brazil, or of Chinese 

 coolies in San Francisco and the Australian colonies. 

 In this respect, our English plants open out a series 

 of interesting problems for the botanical researcher ; 

 because we happen to possess a very mixed and frag- 

 mentary flora, made up to a great extent of waifs and 

 strays from at least three large distinct continental 

 groups, besides several casual colonists. Thus while 

 at Killarney we get a {qw rare Spanish or Portuguese 

 types, in Caithness and the Highlands we get a few 

 rare Alpine or Arctic types : and while in Norfolk 

 and Suffolk we find some central European stragglers, 

 the ponds of the Hebrides are actually occupied by at 

 least one American pond-weed, its seeds having been 

 wafted over by westerly breezes, or carried uncon- 

 sciously by water-birds in the mud and ooze which 

 clung accidentally to their webbed feet. Moreover, 

 we know that at no very remote period, geologically 

 speaking, Britain was covered by a single great sheet 

 of glaciers, like that which now covers almost all 

 Greenland : and we may thercfoie conclude with 

 certainty that every plant at present in the country 



