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Salixnigricans-Weigeliana) is that under which Wimmer describes 

 the plant he received as S. tetrapla, Walker, but which, as already 

 mentioned, appears not to be the true S. tetrapla. Wimmer' s 

 plants,he thinks, were originally from Britain ; and the only habitat 

 he gives for the supposed hybrid is Scotland. Under this name 

 I place all the specimens which cannot be referred positively to 

 phylicifolia or to nigricans. Such examples, though less common 

 than those which can be referred without doubt, are not rarely 

 to be met with, and in a few places are more abundant than either 



phylicifolia or nigricans. 



Andersson does not admit that there is any certain hybrid 

 between S. phylicifolia and S. nigricans, and prefers to consider 

 certain forms, which have been supposed to be hybrids, to be 

 rather modifications of phylicifolia approaching nigricans, or of 

 nigricans approaching phylicifolia. 



The Hybrids between the Phylicifoliae and the Capreae. 



Since in many parts of Britain species of the Phylicifolia and 

 Caprea* groups frequently grow together, and their periods of 

 flowering overlap, hybrid forms occasionally occur. It is not 

 usually difficult to recognize these as hybrids, but it is not always 

 easy to determine the exact parentage. 



Having reduced S. nigricans and S. phylicifolia to the rank of 

 subspecies or major varieties of one willow, the number of the 

 hybrid forms ought perhaps to be likewise reduced ; but since 

 the nigricans, or the phylicifolia, element in the compound is often 

 distinctly marked, it seems expedient to keep their hybrids 

 separate. 



In their most intermediate forms the hybrids of thi3 group 

 show such a combination of the characters of their parents that 

 their compound origin is at once evident ; but, as usual, there are 

 other forms which are not so easily recognized and are still more 

 difficult to describe. The most certain character perhaps is in 

 the structure of the style and stigmas— smaller than in the Phyli- 

 ci foli<e, and larger than in the Caprece ; but there are also usually 

 other good characters in the catkins and in the leaves. 

 Whilst in most cases, though by no means in all, it is possible 



deci(J e whether it is nigricans or phylicifolia that is one of the 

 P^ents, there is often a very considerable difficulty in determin- 

 ing which of the OapretseiB the other, and more especially in those 



orms *We the latter element is the less predominant one. 





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