190 



TREES IN WINTER 



tr 



the self-pruning scar may be nearer the lateral bud which bends in 

 and gives the appearance of being terminal. The presence of a 

 leaf-scar below it shows that it is in fact axillary, 

 but since leaf-scars are sometimes present toward 

 the end of twigs without buds in their axils the 

 presence of the self-pruning scar at the twig end must 

 be used as the decisive sign that the terminal bud is 

 really absent. 



Aside from the color, the presence or absence of 

 hairs, stickiness, fragrance and other such surface 

 characters, the position of the buds in relation to the 

 twig may be of importance. Buds that lie close 

 up against the twig as those of the Small-toothed 

 Aspen (p. 255) are called appressed, while those 

 that project more or less away from 

 the twig as those of the Carolina 

 Poplar (fig. 100)are called divergent. 

 In the Common Locust and a few 

 other forms the buds are sunken 

 below the surface of the twig, and 

 can be found only by cutting the 

 twig lengthwise through the leaf- 

 Fig, 101. Twig scar. 



of Butternut. 



tr— terminai^^ The characters of the bud-scales Fig! 102. Twig of 

 ax-axiiiaryj^^- of most importance are the shape, .^l^^^^n^^y bud. 

 sp— Superposed the number visible in the unmutil- ci— coUaterai 



accessory bud. accessory bud. 



p— chambered arrangement — whether alternate or 



opposite — and the number of ranks they f onn on 

 the bud. 



Fruit — The fruit generally forms a good means of identi- 

 fication when it can be found. Unfortunately there are a number 

 of limitations to its use for this purpose. In the first place many 

 species of trees do not fniit every year, and it may happen that 

 the species under examination is not in its fruiting period and 

 consequently all the trees of the region will fail to show fruit. 

 Again, in some species such as the ilsh the sexes are separate and 

 consequently only female trees can ever be expected to bear fruit. 

 The fruit generally does not remain on the tree throughout the 

 winter but if the tree is sufficiently isolated from other species, 



