126 British Association. 



a series of secondary axes, which are given off in a whorl between 

 the stamens and the primary axis of the flower. These axes termi- 

 nate in imperfect flowers, of which the additional carpels are the 

 only remains. 



Prof. Henslow exhibited a specimen of Papaver orientale, in which 

 the filaments of the stamens were converted into bodies bearing 

 ovules. 



Prof. E. Forbes read a paper on the Endemic Distribution of Plants. 



The hypothesis of the descent of all the individuals of a species 

 either from a first pair or from a single individual, and the conse- 

 quent theory of specific centres being assumed, the isolation of as- 

 semblages of individuals from their centres, and the existence of 

 endemic or very local plants, remain to be accounted for. Natural 

 transport, the agency of the sea, rivers and winds, and carriage by 

 animals, or through the agency of man, are insuflScient means in the 

 majority of cases. It is usual to say, that the presence of many 

 plants is determined by soil or climate, as the case may be ; but if 

 such plants be found in areas disconnected from their centres by 

 considerable intervals, some other cause than the mere influence of 

 soil or climate must be sought to account for their presence. This 

 cause the author proposes to seek in an ancient connexion of the out- 

 posts or isolated areas with the original centres, and the subsequent 

 isolation of the former through geological changes and events, espe- 

 cially those dependent on the elevation and depression of land. Se- 

 lecting the flora of the British Islands for a first illustration of this 

 view. Professor Forbes calls attention to the fact, well-known to bo- 

 tanists, of certain species of flowering plants being found indigenous 

 in portions of that area at a great distance from the nearest assem- 

 blages of individuals of the same species in countries beyond it. Thus 

 many plants peculiar in the British flora to the west of Ireland have 

 the nearest portion of their specific centres in the north-west of 

 Spain ; others, confined with us to the south-west promontory of 

 England, are, beyond our shores, found in the Channel Isles and the 

 opposite coast of France ; the vegetation of the south-east of En- 

 gland is that of the oi)posite part of the continent ; and the alpine 

 vegetation of Wales and the Scotch Highlands is intimately related 

 to that of the Norwegian Alps. The great mass of the British flora 

 has its most intimate relations with that of Germany. The vegeta- 

 tion of the British Islands may be said to be composed of five floras : 

 1st, a west Pyrenean, confined to the west of Ireland, and mostly to 

 the mountains of that district ; 2nd, a flora related to that of the 

 south-west of France, extending from the Channel Isles, across 

 Devon and Cornwall, to the south-east and part of the south-west 

 of Ireland ; 3rd, a flora common to the north of France and south- 

 east of England, and especially developed in the chalk districts ; 

 4th, an Alpine flora, developed in the mountains of Wales, north of 

 England and Scotland ; and 5th, a Germanic flora, extending over 

 the greater part of Great Britain and Ireland, mingling with the 

 other floras, and diminishing, though sHghtly, as we proceed west- 

 Wards, indicating its easterly origin and relation to the characteristic 



