THE DECIDUOUS TREES IN WINTER 73 
distinctive to an unpracticed eye. Then there are tints of 
yellow in the twigs of certain willows, and of red in the twigs 
of the red maple and in the swollen buds of the linden. 
Trees grown in the open develop a characteristic form and 
are recognizable by their general outline. Most strict and 
cylindric is the Lombardy poplar; most inclined and spread 
out upward into vaselike form is the beautiful and stately 
American elm. Most smoothly oval is the sugar maple and 
most nearly hemispherical is the apple. The soft maple and 
the hickories and many others take on an irregular 
and ragged outline. It is to be noted at once that in their 
youth these trees are all much more alike in 
form; also, that in the forest, close crowding 
reduces every kind of tree to a tall and 
slender trunk holding aloft as a crown the 
few branches that have been able to reach 
the light. 
Much more dependable recognition char- 
acters are found in the structure of the tree- 
top. The trunk may tend to form a single 
axis as in the birch, or to split up early 
into long main branches asin the elms. The 
boughs may be short and stocky asin an old 
chestnut, or long and slendér as in a beech. 
The twigs may be long or short stout or slen- 
der, and in position ascending, horizontal, or 
drooping. The bark may present many 
characteristic differences on trunk and bough 
G¢SSPs 
Fig. 41.  Dia- 
gram of forms 
of leaf scar, 
andof grouping 
of bundle scars 
on twigs of: a, 
catalpa;b,black 
ash; c¢, horse 
chestnut; d, 
mockernut hic- 
kory; e, black 
walnut, 
and twigs, all of which need to be seen to 
be appreciated. But most positive of all 
the structural differences by which we may 
distinguish trees are some of the lesser 
characters in bud and leaf scar, a few of 
which are indicated in figure 41. The size 
