50 
T. vulgaris, T. europaea and T. intermedia. The leaves, which are in¬ 
termediate in size between those of its supposed parents, are dull 
green on the upper surface, pale on the lower surface and destitute of 
hairs with the exception of those which form the clusters in the axils 
of the veins. The largest and handsomest Linden-trees in the neighbor¬ 
hood of Boston are this hybrid and larger and handsomer specimens 
can sometimes be seen in the Middle States. The shapely and healthy 
young trees which have been planted to shade the Louis Pasteur Ave¬ 
nue in Boston are good specimens of this tree and show what city 
street-trees should be. 
The two Lindens of eastern Europe, T. tomentosa and T. petiolaris, 
are distinct and handsome trees with leaves silver white on the lower 
surface, which can be easily and successfully grown in southern New 
England. T. tomentosa, which is common in the forests of Hungary, 
in this country forms a broad, compact, round-topped head with erect 
branches and large leaves erect on short stalks. T. petiolaris is a more 
beautiful tree with pendulous branches which form a narrow head, and 
with leaves drooping on long slender stems. It has proved to be one of 
the handsomest exotic trees which can be planted in the eastern states. 
It is too soon to speak with authority on the value of the Asiatic 
Lindens. Only T. japonica has been long enough in this country to give 
any real indication of its value. It is a graceful and handsome little 
tree which is the first of the Lindens in the Arboretum collection to 
flower, but as yet shows no indication of growing to the great size this 
tree attains in Japan. Some of the most valuable of the Lindens are 
hybrids. Attention has already been called in this Bulletin to Tilia 
vulgaris. The Crimean Tilia euchlora is believed to be the natural 
hybrid between T. caucasica and T. cor data. One of the handsomest 
Linden-trees in the Arboretum, T. spectabilis, is supposed to be a hy¬ 
brid of T. glabra and T. petiolaris. It is a fast-growing tree with 
leaves as large or larger than those of T. glabra but silvery white below 
like those of its other parent. A variety of this hybrid called “Moltke” 
originated many years ago in a German nursery. It is a tree of denser 
habit and darker leaves than T. spectabilis and grows well in the Ar¬ 
boretum. 
In North America fifteen species and a few varieties of Linden-trees 
are now recognized; that is more than in all the rest of the world. 
One of the northern species, Tilia glabra or americana as it is still often 
called, is the American species which has been most often cultivated; it 
is a splendid tree at the north and although usually much smaller reaches 
occasionally the height of 120 feet with a trunk from three to four 
feet in diameter. This tree is easily distinguished by the lustrous 
under surface of the leaves which are destitute of hairs with the ex¬ 
ception of those which form on the lower surface the conspicuous 
rusty brown axillary tufts. This tree has been much planted in Can¬ 
ada and the northern states as a park and street tree; it is more sat¬ 
isfactory northward for in southern New England and the Middle States 
the leaves especially on street trees are often disfigured by red spiders 
which however can be kept in check by dry sulphur spray. The second 
northern species, Tilia neglecta, although it was described many years 
ago in Europe from cultivated trees was not recognized by American 
botanists and tree lovers until a comparatively short time ago. This 
