26 FAMILIAR TREES 



by the fertilisation of the stigma of one species by 

 the pollen of another) occur frequently, not only in 

 withy-eyots, but also in a truly Avild state. This 

 and some other variation has caused some seventeen 

 well-marked British species to give rise to nearly a 

 hundred puzzling forms. 



It will be remembered that Willows are 

 " dioecious " ; and this is the explanation of the 

 children's distinction between "golden palms" and 

 " silver pussy palms " — the former, though bearing at 

 first a tuft of silvery down within the brown bud- 

 scales, soon becoming studded with the yellow 

 anthers, while the latter bear only the down-clad 

 ovaries, which resemble the grey fur of a cat. 



Though belonging mainly to the Arctic and North 

 Temperate zones, there are a few Willows in temper- 

 ate South America and South Africa ; and the species 

 are very diverse in the situations, or " habitats," 

 which they frequent. Thus, while Osiers are almost 

 confined to spots where their roots are liable to be 

 soaked with flood-waters, and many other species 

 are fond of moisture, the Sallows, such as S. Cap'rea, 

 flourish in dry woods and hedgerows, and several 

 species inhabit the barren tops of Alpine moun- 

 tains, or the equally barren plains of Arctic latitudes. 

 So, too, do they vary in size, from the White Willow 

 (S. alba L.), a tree sometimes eighty feet in height, 

 the Crack Willow (8. fra'gilis L.), which attains an 

 equal, if not greater, height, with a girth of as much 

 as twenty feet, down to the prostrate S. reticulata L., 

 under two feet in height, and the still smaller S. her- 

 ba'cea L., the most diminutive of British shrubs. 



