TREE FORMS IN WINTER 249 



heaviness of its trunk and boughs, whereas the lime has 

 slender boughs, and a trunk no more than proportionate to 

 the total mass. The branches of the lime decrease gradually 

 and evenly to the outer twigs, which are fairly dense, though 

 less abundant than those of the elm or birch. The chestnut's 

 branches dwindle very rapidly, and there is little interval 

 between the large limbs and the leaf-bearing sprays. The 

 limbs are spreading though comparatively short, and are free 

 and picturesque in growth. The bark of young limes is 

 smooth ; after the tree reaches full growth it splits into 

 shallow and regular ribs and furrows. Chestnuts have bark 

 strongly grooved in a shallow network, with a wide interven- 

 ing rib. It is softer in appearance than that of the ash 

 or oak, or most other trees, with parallel rather than flaky 

 sculpture ; the ribs and grooves often run obliquely or spirally 

 up the trunk, as is sometimes seen in pines and firs. This 

 is probably due to the unequal development of different sides 

 of the tree during growth. The massiveness and free growth 

 of the sweet chestnut make it a fine tree even in our climate, 

 where it is not quite at home. It is a native, like the walnut, 

 of central and southern Europe ; and it grows more freely 

 and abundantly in a characteristic zone of culture midway 

 between the high pine forests of the Alps and Pyrenees and 

 the plain. The horse-chestnut belongs to a different family, 

 and is believed to have come originally from the Balkan 

 peninsula. It is easily distinguishable when bare of leaves 

 and blossoms, owing to its rounded head, the smooth and 

 regular lines of its limbs, the blunt tracery of its outer twigs, 

 and the appearance of the bark. On the trunks of young 

 trees and on the boughs this is smooth and unusually dark. 

 The boles of old trees have grey and scaly bark, something 

 like that of the sycamore, but with thicker and rougher 

 flakes. These three trees well illustrate the different degrees 



