Complimentary 
NEW SERIES VOL. II NO. 1 1 
ARNOLD ARBORETUM 
HARVARD UNIVERSITY 
BULLETIN 
OF 
POPULAR INFORMATION 
JAMAICA PLAIN, MASS. JULY 6. 1916 
Lindens are the most important of the summer-flowering trees in 
this climate, and many of the plants in the Arboretum collection are 
now large enough to flower and to be interesting; although none of 
them are old enough to show the form and bark of mature trees. 
Linden trees are very generally distributed in all the temperate regions 
of the northern hemisphere with the exception of western North 
America, and, in addition to numerous species, several hybrids are 
cultivated. All the species are very similar in flower and fruit, and 
chiefly vary in the size and shape of their leaves, in the presence or 
absence of hairs on the leaves and branchlets, and in the nature of 
their hairy covering when it occurs. A fact not easy to explain is the 
presence in the flowers of all the American species of five petal- 
like scales opposite the petals and connected with the clusters of 
stamens, while in the flowers of all the Old World Lindens such scales 
do not exist. It is almost a universal rule that the trees of eastern 
North America and eastern Asia are more successful here in cultiva- 
tion than those of Europe, but an exception is found in the Lindens. 
All the European species and many of their hybrids flourish here and 
some of them have grown in Massachusetts to a large size. Of the 
American species cultivated plants of the northern T. americana 
suffer greatly, especially when used as street trees, from the attacks 
of the red spider which often badly disfigures the leaves, and the 
leaves of this tree suffer, too, from various fungal diseases. The sil- 
ver-leaved T. heterophylla from the South may do better in this part 
of the country but not much is yet known of it as a cultivated tree. 
There are other Linden trees, natives of the extreme southern states, 
but none of them have been cultivated except occasionally in southern 
towns. Judging by the results obtained in the Arboretum none of the 
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