THE SION VISTA AND THE THAMES 187 
suberosa ; in this variety the younger branches are furnished with 
conspicuous ridges of corky bark, which give the whole tree a very 
distinct appearance. The variegated varieties, as well as the pen- 
dulous and erect-growing ones, are also noteworthy, and afford a 
good selection of garden trees. Near the Brentford Gate are planted 
several of the allies of the elm — Zelkowa, Planera, and Aphananthe. 
After the elms come the poplars, comprising such well-known 
trees as the aspen, abele, cottonwood, and balsam poplar. The 
ground here is too sandy and dry for these trees, and 
Birches ^ ere are n0 ^ man Y °I large size. The birches alone 
remain to claim our notice, and they can easily be 
seen from afar by the large proportion of silvery trunks among them. 
The native birch is a beautiful tree ; no other birch is more graceful, 
but some, like the “paper” birch of North America and the Japanese 
Betula ulmifolia, are even more striking for their silvery-white trunks. 
In contrast, the dark, shaggy trunks of the North American river- 
birch will attract attention. In all, more than twenty species are 
grown here, besides numerous varieties. 
Thus ends our tour. Without allowing for any deviations, it 
has given us a walk of three miles or more since we left the clematis 
near the Victoria Gate. We are now close to the big open lawn in 
front of Kew Palace. By crossing this towards the Museum (No. III.) 
we shall reach the Broad Vhdk and the Main Entrance. 
