358 
THE NATIONAL NURSERYMAN 
LINDENS AT THE ARNOLD ARBORETUM 
The largest genus of summer-flowering trees here is 
Tilia,*^the Lindens, which are now (July) at the height of 
their flowering time although the flowers of a few of the 
species are already fading and those of some others are 
just opening. The genus is widely and generally distributed 
in all the temperate parts of the northern hemisphere mth 
the exception of western North America and the Himalayas. 
Between forty and fifty species and several hybrids are 
recognized, for hybrids and supposed hybrids' in Tilia are 
common, and among these hybrids are some of the hand¬ 
somest and most rapid-growing of all Lindens. Although 
Lindens are much planted for the embellishment of parks 
and as street trees there is great confusion, especially in the 
United States, in regard to the different forms which are 
cultivated, and this confusion in so far as it relates to the 
European speeies was imported from Europe with the trees, 
for Linnaeus and many botanists after him believed that 
the Lindens of northern and western Europe were only 
forms of one tree, and so started the trouble. 
In eastern North America there are seven species of 
Linden trees; four of these are from the extreme south 
and either are not hardy in the Arboretum or have been 
tried here during such a short time that they need not now 
be considered. The Linden of the north, T. americana, is 
a splendid great tree growing to its largest size on rich hill¬ 
sides and moist bottom-lands, and showing its greatest 
beauty in the forests of New Brunswick, northern New 
England and the valley of the St. Lawrence River. This 
tree may be easily distinguished from the other Lindens by 
the green and shining lower surface of the leaves which 
has no hairy covering with the exception of rather conspicu¬ 
ous tufts in the axils of the principal veins. This tree has 
been somewhat planted in eastern Massachusetts but less 
frequently than in the neighborhood of more northern cities. 
Here, especially in dry summers, the leaves are sometimes 
made brown by the red spider which, however, is easily 
controlled by spraying. Tilia spectabilis, which is believed 
to be a hybrid between this tree and Tilia tomentosa of 
eastern Europe, is a very vigorous and fast-growing tree of 
much promise. In some European nurseries it is sold under 
the name of Tilia Moltki. Tilia flavescens, usually found in 
nurseries under the name of T. floribunda, is a supposed 
hybrid between T. americana and the European T. cordata. 
This tree is remarkable in its rather small, thick and very 
lustrous leaves, and large flowers. Plants only a few feet 
high flower profusely. 
The second North American Linden tree, T. alba, or, as 
it is often called, T. Michauxii, although it was first dis¬ 
tinguished and made known nearly a centimy ago, was long 
overlooked or mistmderstood by botanists; and it is only in 
recent years that this handsome tree has been found to be 
widely distributed from the valley of the St. Lawrence 
River to Georgia and Arkansas. It may be distinguished 
from T. americana by the pale lower surface of the leaves, 
which is more or less covered with star-shaped clusters of 
white hairs. This tree is now wellj^established in the 
Arboretum, although the plants are not old enough to 
flower. 
The third of our northern Lindens, T. heterophylla, is a 
species of the Appalachian Mountains and is distributed 
from western New York to northern Alabama, and through 
Kentucky to southern Indiana and Illinois, growing to its 
greatest beauty and to its largest size in the forests which 
cover the slopes of the mountains of North Carolina and 
Tennessee. The leaves of this tree are larger than those 
of the other Lindens, and as they are silvery white on the 
lower surface and hang on long, slender stalks the slightest 
breeze makes them tm*n first one surface and then the other 
to the eye. This hardy and beautiful tree appears to be 
rarely cultivated. 
All the European Lindens succeed in the eastern states 
where they have been more generally planted than the 
American species and where there are large and old specimens 
of some of the species in the neighborhood of the seaboard 
cities. There are five European Lindens and it is among 
these and their hybrids that exists the greatest confusion 
in the minds of the cultivators of these trees. Probably 
the most widely distributed of the European species, especi¬ 
ally in the south, is Tilia platyphyllos. This tree may be 
recognized by the yeUow tinge of the leaves and the thick 
covering of short hairs on their lower siuface and on their 
stalks ,and by the prominent ribs of the fruit. This is the 
earliest of all Linden trees to flower here, the flowers having 
been fading for the last ten days, and it is this tree which 
now appears to be most commonly sold in American nurseries 
as the European Linden. There are varieties with leaves 
larger than those of the type (var. grandifolia) , with erect 
branches forming a broad pyramidal head (var. pyramidata), 
and with variously divided leaves (var. lanceolata and 
vitifolia.) 
A more beautiful tree is Tilia cordata, the common Linden 
of northern Europe where it sometimes grows to a very 
large size, the old historic Lindens of the northern and 
central parts of the continent being usually of this species. 
This tree is distinguished by its small, thin, more or less 
heart-shaped leaves which are pale on the lower surface 
and furnished with conspicuous tufts of rusty brown hairs 
in the axils of the principal veins. It appears to have been 
little planted in the United States, and in the neighborhood 
of Boston it is the rarest of the Lindens of western Europe. 
It is, however, a hardy and desirable tree especially valuable 
on account of its late flowers which supply the bees with 
food after those of all other Lindens have passed. There is 
a large-leaved form of this tree (var. cordifolia) from western 
Emope in the collection which is a handsome and vigorous 
plant of much promise. This is sometimes sold in European 
nurseries as T. europaea or vulgaris. 
The third European Linden, called variously T. vulgaris, 
T. europaea, T. intermedia and T. hybrida, is considered by 
some of the best observers of European trees a natural 
hybrid between T. platyphyllos and T. cordata. Although 
widely distributed in Europe, it appears to be much less com¬ 
mon than either of its supposed parents, and the variation 
in the size, shape and color of the leaves make its hybrid 
origin possible. On some individuals the lower surface of 
the leaves is quite green and on others it is bluish or^even 
whitish, but leaves on different parts of the same branch 
