88 



THE WILLOW FAMILY SALICACEAE. 



The Willow family comprises about 200 species belonging to two 

 genera, the well-known Willows and the Aspens or Poplars. The 

 members of this family comprise both trees and shrubs found chiefly 

 in the north temperate and arctic zones. A few shrubby species 

 extend far into the arctic regions. They usually prefer moist habi- 

 tats but may also be found on drier locations. One is very apt to 

 associate the Willows with wet habitats. 



The flowers appear in early spring, usually before the leaves. 

 The staminate (male) and pistillate (female) flowers are produced 

 on different trees. A tree bearing staminate flowers does not bear 

 the pistillate. As a consequence one will find fruit only upon pis- 

 tillate trees. The pistillate flowers are fertilized by insects, usually 

 bees, which carry the pollen from the staminate flowers. The fruit 

 consists of capsules which split into 2-4 parts and are arranged in 

 drooping tassel-like clusters. The fruit matures in late spring at 

 about the same time that the leaves reach their full size. The seeds 

 are small and surrounded by a dense covering of long white hairs 

 which aid considerably in their dispersal. The seeds must germinate 

 soon after they mature or they will lose the power of germination. 

 The bark is usually rather bitter. 



The representatives of both genera are noted for their remarkable 

 ability to grow both from root and shoot cuttings. One can cut a 

 small twig from a tree, put it into moist ground, and feel assured 

 that it will grow. They also sprout very freely from stumps ir- 

 respective of the age of the stump. The following key will distin- 

 guish the two genera belonging to this family. 



KEY TO THE GENERA. 



Page. 

 1. Buds with one bud-scale; bracts of the catkins entire; stamens fewer than 10, usually 



2 Salix 88 



1. Buds with more than one bud-scale; bracts of the catkins fringed or lobed; stamens 



usually 10 or more Fopulus 94 



THE WILLOWS SALIX (Tourn.) L. 



This genus comprises about 175 species of which number about TOO 

 species are native to North America and about 15 species to Pennsyl- 

 vania. The members of this family are met as trees and shrubs. 

 Most of our native species are small trees or shrubs. Those which 



