BRITISH FOREST TREES 319 



5. WILLOWS (SALIX). 



The genus Satix, which together with Populus makes up 

 the order Salicaceae^ contains, according to Andersson, about 

 1 60 species in addition to a host of hybrid varieties or cross- 

 breeds ever increasing in number. Of these about fifty to 

 sixty occur in central Europe, but the number is already re- 

 duced to about thirty in Britain, although on this point opinion 

 is far from being unanimous. When leafless in winter, it is 

 often difficult to decide to which genus a tree belongs, until 

 twigs have been obtained and examined, when the following 

 general macroscopic distinctions will be noticeable : 



Salix Terminal bud usually wanting ; buds enclosed in one large- 

 scale compressed at both sides, and situated immediately 

 over the three punctured leaf-scar ; floral bracts entire. 



Populus Develops true terminal buds ; buds enclosed in several 

 spirally arranged scales or bracts, often gummy or resinous ; 

 flowers in the axils of divided bracts. 



The willows that are of greatest sylvicultural value may 

 be arranged as follows : 



Tree Willows: 



I. .9. caprea, L., saugh, sallow, goat willow, or great round- 

 leaved willow. 



IS. Kusselliana, the 

 Russell or Bedford 

 will<nv, is said to 

 be a cross between 

 these two species. 

 Osiers, twig, shrub, or basket willows, or withies : 



1. .9. ?>i mi nalis, L,., the osier. 



2. S. triandra, L. (including .S'. amygdalina, L.), the laurel osier. 



3. .V. purpurca, L. , the purple osier. 



S. rubra Huds. (= S. helix, L.), the red osier, is said to be a cross 

 between S. viminalis and pur pur ea. 



Distribution. The tree-willows enumerated appear to be 

 all indigenous to Britain, and have a wide distribution 



