34 
vivor of a race which was once widely spread over the northern hem- 
isphere, this inhabitant of eastern continental Asia is long-lived and 
able to support extremes of heat and cold, and to grow equally well 
in Massachusetts, Georgia and California. The Gingko is appreciated 
and has been largely planted in the city of Washington, but in other 
parts of the United States the beauty of this tree when it gets beyond 
its juvenile habit is not understood. Pseudolarix is another Chinese 
tree which is alone in its class and, although discovered only seventy 
years ago, it has been long enough in this country to show that it is 
perfectly able to adapt itself to the Massachusetts climate. This is 
surprising for the home of Pseudolarix is on low miountain slopes not 
far from the coast and south of the Yangtse River. The European 
Larch, although less picturesque than the Larch of northeastern North 
America, is a larger and more valuable tree, and the experience with 
it in New England shows that it is a tree which can be depended on 
to grow here rapidly to a large size. 
The two Silver Poplars of Europe {Populus alba and P. canescens) 
flourish in the United States where they have grown to a large size 
and are as much at home as they are in their native countries. The 
pale color of the foliage of these trees is unlike that of any of the 
American species, and their hardiness and vitality make them useful 
for planting in exposed positions. The Silver Poplar of northern China 
(P. tomentosa) is one of the handsomest of all Poplar-trees. It has 
grown well in the Arboretum but it is too soon to form an opinion of 
its value in this country. Two European Willows, Salix alba, and «S. 
fragilis, and some of their varieties, have become completely naturalized 
in the northeastern states where they grow as large or even larger than 
in Europe and are important additions to the North American silva. 
The Chinese Weeping Willow {S. babylonica) is not always perfectly 
hardy in Massachusetts, but further south is valued as an ornamental 
tree. The so-called Wisconsin Willow, a natural hybrid between this 
Chinese Willow and S. alba, and other hybrids of the same parentage 
are useful ornamental trees in the northern states. 
Cercidiphyllum is the largest deciduous-leaved tree of Japan, and 
although it was introduced into the United States only forty years ago 
it gives promise of becoming a permanent addition to the trees of the 
largest size which can be successfully grown here. The Chinese White 
Mulberry {Morus alba) is a larger and hardier tree than the Mulberry- 
tree of the eastern states, and is perfectly at home here. Probably 
the most generally useful, however, of the large deciduous-leaved 
trees which have been brought into the northern states is the Ailan- 
thus of northern China which must have been growing here for nearly 
a century. It grows rapidly and is perfectly hardy, and it can resist 
the heat, drought and dryness which trees have to suffer in our cities 
better than any other tree with the exception, perhaps, of some of the 
Poplars. The Ailanthus, too, produces handsome wood valuable in cab- 
inet-making. 
The Japanese White Oaks are handsome trees and produce valuable 
timber. They grow well in the Arboretum and give every promise of 
