368 DR. F. BUCHANAN WHITE'S 



The question is, therefore, which of these two parties is right, 

 a question which, it seems to me, it is almost, if not quite, im- 

 possible to decide. I am inclined to think that it is not unlikely 



Salixfi 



If this claim 



could be proved, then A would = 8. Bwselliana, Sm., and A X B 

 would = S. fragili*, L. ; but as there is so much uncertainty, and 

 as an adoption of Smith's views would entail great synonymic 

 changes, it seems more expedient to follow Koch, &c, and to con- 



fi 



fragilis 



3. Salix fragilis, L. 



8. fragilis, as it has just been defined, namely, with 8. viridts 

 as well as S. decipiens eliminated from it, is not, as it occurs in 

 Britain, a species subject to any great range of variation. 



The points of distinction between it and S. decipiens have 

 already been pointed out, and those between it and S. viridts 

 may be better considered when treating of that plant. Though 

 in Britain, as in Continental Europe, there is no great difficulty 

 in distinguishing it from S. alba, yet it is so closely allied to the 

 latter, that, as Andersson remarks, in some regions of Asia they 

 are united by so many forms, that it is not easy to point out the 

 difference between them. For this reason, he thinks that pos- 

 sibly it originated there, and has thence immigrated into Europe. 

 If this be the case, it must have occurred at a very early period, 

 if Saporta is right in his determination of certain plant-remains 

 of the Pleistocene tufa of the Seine valley, not to mention 

 Heer's discoveries in Swiss Miocene deposits. Be that as it may, 

 S. fragilis is, at the present day, in Britain as native, to all appear- 

 ance, as most other species of lowland willows. 



As mentioned above, 8. fragilis does not in Britain show any 

 great range of variation ; but an examination of any extensive 

 series and a comparison with Continental specimens will show that 

 there are two tolerably distinct forms which seem worthy to rank 

 as varieties. These may be called a. genuina and /3. britannica ; 

 and the distinctions between them lie chiefly, if not entirely, in 

 the flowers. In a the cf catkins are rather dense-flowered, with 

 the stamens conspicuously longer than the scales, whilst in /3tbe 

 catkins are lax-flowered, and the stamens are scarcely longer than 

 the scales. Hence in a the stapaejis and in /3 the scales form the 

 conspicuous feature of the catkins. In the $ the differences 



















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