B48 TREES OF MINNESOTA. 
Acer negundo. (Negundo accroides.) Boxelder. Ash- 
leaf Maple. 
Leaves opposite, pinnately compound with three to five 
leaflets. Flowers dioecious, apetalous small, greenish, appear- 
ing just before or with the leaves. The sceds are oval in form, 
ripen in autumn, and hang on the trees until winter in this sec- 
tion. Many trees bear fruits that to outward appearance con- 
tain perfect seeds but which upon examination will be found 
to be empty seed vessels. 
Distribution—One of the most widely distributed and hardi- 
est trees of North America, ranging from the valley of the Sas- 
katchewan to Florida and Texas and from Vermont to the east- 
ern slopes of the Rocky Mountains. In the Minnesota river 
bottoms this tree grows seventy feet high and three feet in 
diameter, while in severe locations it becomes a low bushy tree. 
Propagation.—By seeds sown as soon as ripe in the fall or 
stratified over winter and sown in the spring. 
Propertics of wood.—Light, soft, close grained, but weak. It 
is creamy white, with thick, hardly distinguishable sapwood. 
Specific gravity 0.4328; weight of a cubic foot 26.97 pounds. 
Uses.—The Boxelder is one of the hardiest of trees, and 
is highly esteemed for street and lawn planting and for wind- 
breaks in severe locations. It has, however, been too often 
planted where the White Elm or Green Ash should have been 
used. The wood makes good fuel; it is sometimes used for 
interior finishing, woodenware, paper pulp, ete. Maple sugar 
is sometimes made from this tree, though the sap is not so rich 
in sugar as the sap of the Sugar Maple. 
HIPPOCASTANACEAE. BUCKEYE FAMILY. 
An order consisting of two genera, the following of which 
contains about fifteen species natives of America and Asia. 
None are native of Minnesota. 
Genus ASSCULUS. 
Leaves opposite, digitate, three to nine-foliate. Flowers in a 
terminal dense panicle, often polygamous, most of them with 
