

398 



DR. F. BUCHANAN WITTTB S 





retained in the British list. The characteristics of these consist 

 in the shape of the leaves and in the amount of pubescence on the 

 capsule and its stalk. An examination, however, of any consi- 

 derable number of specimens will show that not only may the 

 leaf-characters of one variety and the capsule-characters of 

 another be present in one and the same specimen, but that both 

 downy and glabrous capsules may occur in the same catkin. 

 Leefe also has pointed out that under cultivation a smooth capsule 



may become pubescent. 



Whilst there is probably no doubt that the plants on which 

 the supposed species or varieties were originally founded showed 

 considerable distinctness, their characters are those of individuals, 

 and these almost all cultivated specimens. Moreover, quite dii- 

 ferent forms have not only been called by the same name by 

 botanists who are supposed to have known the varieties, but have 

 been figured and described. Since, then, these varieties do not 

 exist in nature as constantly distinct entities, the varietal names 

 can be no longer retained. 



Of the varieties ascribed to Salix phylicifolia, one or two may 

 be noticed more specially. 



S. ietrapla, Walker, being, according to Wimmer, the same 

 his S. phylicifolia-nigricans, has been considered by some authors 

 to be, if not a hybrid, a connecting-link between phylicifolia and 

 nigricans. But, as Wimmer himself points out, his specimens 

 (received from the Berlin Botanic Grarden) do not agree with the 

 English figures. Leefe's specimens (Sal. Exs. i. No. 8), 

 ceived from Mr. Borrer as the plant of Walker," differ from 

 Wimmer's, and agree with Sal. Wob. t. 49, and appear, without 

 doubt, to belong to a. S. phylicifolia. Hence Wimmer's deter- 

 mination (and the theories founded on it) of S. tetrapla, Walker, 

 must be considered as erroneous, though his specimens seem 

 probably referable to S. phylicifolia-nigricans. 



S. Crowcana, Sm. — It is probable that under this name two 

 plants are confounded — one an abnormal condition of phyhc l ~ 

 folia, the other a hybrid of that species with S. purpurea. The 

 essential characteristic is the combination of the filaments of the 

 stamens for a greater or less part of their length, as in S. rubra. 

 But the union of stamens may originate in two ways — one fl° r * 

 mally, by hybridization with the Salices Synandra ; the other 

 abnormally, by cladostemmy. Im the latter the branches of the 

 filament are said to form an obtuse angle, in the former an acute 







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