













KEVISION OF THE BBITJSH WILLOWS 



347 















































VI. Beyisiojt of the Species. 



. A. PLEIANDILE. 

 Group I. Tbiandbjs. 

 1. Salix triandra, L. 



Smith and his school of salicologists considered that the willow 

 which is now known as S. triandra, included three, if not four, 

 distinct species, viz. 8. triandra, L., 8. amygdalina, L., 8. Hoff- 

 manniana, Sm., and perhaps S. contorta, Crowe, — distinguished 

 by the shape, size, and colour of the leaves, and nature of the 

 shoots. Continental botanists, on the other hand, while not 

 usually recognizing all these, separated from S. triandra several 

 other forms. At the present day none of these forms are recog- 

 nized as species, though most of them are retained as varieties, 

 at least by the British school. Thus, in the last edition of the 

 1 London Catalogue ' four varieties of S. triandra are given, 

 namely, a. amygddlina (L.), b. Hqfmanniana (Sm.), c. Trevirani 

 (Spreng), and d. contorta (Crowe). 



The majority of continental salicologists, as Koch, Grenier, 

 and Andersson, make the more important varietal characters lie 

 in the colour of the leaves, while Wimmer considers the shape 

 to be of more value. 



Andersson's leaf-varieties are a. discolor, Koch (underside of 

 leaves intensely glaucous), and /3. concolor, Koch (paler but not 

 giaucous). Of each of these there are the forms 1. latifolia, 

 2. angustifolia, and 3. microphylla. He also gives two catkin 

 varieties, y. tenuijulis and h. crassijulis. 



Wimmer's varieties are a. vulgaris, ft. angustifolia, and y. Vil- 

 larsiana, each with modifications according as the underside of 

 the leaves is green or glaucous. 



On the whole, Andersson's division into discolor and concolor 

 seems to be the arrangement most worthy of retention ; since au 

 examination of any large series will show that the variations 

 dependent upon sh.ipe, whether of the leaves or of the catkins, 

 are all connected by intermediates and glide the one into the 

 other. But the presence or absence of glaucosity is not a suffi- 

 ciently stable character, either, upon which to found varieties ; for, 

 as Wimmer remarks, not only may glaucous and green leaves be 

 found on the same plant, but even the same leaf may be partly 

 green and partly glaucous below. It seems better, therefore, to 

 Place little importance on any of the so-called varieties— either 

 British or continental— of S. triandra. 



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