51 
There is a form with erect branches forming a narrow pyramidal head 
and others with leaves more coarsely toothed than those of the ordinary 
form, and with purple and other abnormal leaves. This is perhaps the 
least beautiful of all the species of Elms. The abundant seeds are blown 
great distances and germinate so readily that seedlings are often trouble- 
some weeds which if neglected for a few years become difficult to erad- 
icate. For several years the leaves of this tree in the neighborhood 
of Boston have been turned brown and often killed by a leaf-mining 
insect which attacks this species but no other Elm-tree. 
Ulmus minor, sometimes called U. sativa, is a small-leaved Elm-tree 
of large size which is rather closely related to U. foliacea. Although 
common in the eastern counties of England, it is possible that this tree 
cannot be seen in the United States outside of the Arboretum. 
Ulmus hollandica. This general name has been given to a race of 
natural hybrids between U. foliacea and U. glabra, among which are 
some of the handsomest and most valuable of the European Elms. To 
the best known in this country of these hybrids the name Ulmus hol- 
landica vegeta has been given. This tree was raised in a nursery at 
Huntingdon about the middle of the eighteenth century and is usually 
called the Huntingdon Elm. This tree often grows one hundred feet 
high with a massive trunk and spreading and ascending branches which 
make a vase-shaped head which readily distinguishes this tree from other 
Elms. It can be seen to good advantage in Cambridgeshire, England, 
especially in Cambridge, where there is a noble avenue of the Hunting- 
don Elm. A tree of this hybrid which grew in the grounds of Magda- 
len College at Oxford was believed to be the largest tree in Great 
Britain. In this country this tree grows more rapidly than other Elm- 
trees, and as it produces suckers it can be easily multiplied. It is not 
common here, however, although in the neighborhood of Boston speci- 
mens not more than sixty years old have already grown to a large size. 
The var. belgica of this hybrid is the Elm which has been most often 
planted as a street and roadside tree in Belgium and Holland. It is a 
tall tree with a straight, rough-barked trunk, a broad head of rather 
erect branches, and dark green leaves slightly roughened above and 
covered below with soft down. As this tree grows in Holland it is one 
of the handsomest and most desirable trees for shading city streets. 
This Elm appears to be little known in the United States; it is grow- 
ing well in the Arboretum, but it*has not been here long enough yet 
to show if it will be of permanent value in New England. The so- 
called Dutch Elm, Ulmus major of many English dendrologists and a 
common tree in English parks, is probably another hybrid of the same 
parentage {U. hollandica var. major). This is a large tree with a short 
trunk covered with rough bark, wide-spreading branches furnished with 
corky wings, and dark green leaves lustrous and nearly smooth on the 
upper surface and slightly downy below. As this tree produces many 
suckers it can be easily multiplied. 
The Arboretum collection now contains sixty-six different Elms and 
includes all the known species with the exception of the four Himalayan 
Elms and the Mexican Elm which are not in cultivation, and two spe- 
