370 Disli'ibiition of Certain Elements of the British Flora. 



(Irying-up mud on the margin of the pool, associated with : 

 Polygonum minus, P. Hydropiper , Limosella aquatica, Radicula 

 Palustris and Callitriche. On the bare mud it was semi- 

 prostrate. Further from the water among the Polygonum it 

 was more erect and two or three inches high. 



There does not appear to be any reason why this plant 

 should not be a true native, as it is in grounds that are seldom 

 visited, and in many seasons it is probably covered by the 

 water, in the same way as the species of Elaiine and Subularia. 



Dr. G. C. Druce has kindly examined the plant, and he 

 agrees that it is probably native there or brought there by 

 natural rpeans. 



DISTRIBUTION OF CERTAIN ELEMENTS OF 

 THE BRITISH FLORA.* 



J. R. MATTHEWS, M..\. 



A CARTOGRAPHIC study of Certain portions of the British Flora 

 is made. Flowering Plants only are dealt with, Babington's 

 Manual of British Botany being used as a basis for analysis. 

 Data relating to distribution in the British Isles are taken 

 from Watson's Topographical Botany and Lloyd Praeger's 

 Irish Topographical Botany, while, for continental distribution, 

 reference is made to Nyman's Conspectus Florae Europaeae. 



The portions of our Flora, the distribution of which is 

 presented cartographically, do not correspond exactly to those 

 elements that have been variously described as Iberian, At- 

 lantic, Germanic, Scandinavian, etc., but are defined geo- 

 graphically in terms of their distribution within the British 

 Isles. Thus, plants of the British Flora confined to England 

 are mapped collectively. Plants occurring in England and 

 freland, but not in Scotland, are treated as another portion, 

 and are similarly mapped, and so on. It is obvious that 

 map.i thus obtained will help to visualise the mass distribution 

 of these portions of our Flora, and taken in conjunction with 

 the European distribution of the same plants, they may help 

 to substantiate one or other of the numerous views held in 

 regard to that migration of plants from the continent which 

 re-populated these islands after the Glacial Period. The 

 exact effects of the glaciation of Britain on the Flora are still* 

 disputed, and until Geologists come to the aid of Botanists in 

 this matter, the latter will continue to have no definite 

 starting-point. But there is sufficient (^vicU'nce to IhUinc 



* .\l)stract of i)a])i'r n acl to tlio J'.iitisli .Vs; ociatinn at ]-!dinbiiii;h . 



Naliir;ilibl 



? 



