DICOTYLEDONOUS PLANTS 141 
stipules. Flowers regular, mostly somewhat moncecious or 
dicecious, in axillary and terminal cymes or racemes. Calyx 
4_9-parted. Petals as many as the lobes of the calyx or 
none. Stamens 4-12, hypogynous. Ovary 2-celled ; styles 2. 
Fruit a double key.* 
ACER, Tourn. 
Characteristics of the genus as above given for the family. 
1. A. saccharinum, L. (A. dasycarpum, Ehrh.). WHITE MapLe, 
River Mapte. A tall tree with the main branches slender and 
rather erect. Leaves very deeply 5-lobed, with the notches rather 
acute, silvery-white, and when young downy on the lower surface, 
the divisions narrow, coarsely cut and toothed. Flowers greenish, 
in umbel-like clusters, appearing long before the leaves. Petals 
absent. Fruit woolly at first, then smooth, with diverging wings, 
the whole 2-3 in. long. Common on river banks S. and W., also 
planted for a shade-tree, but not safe, as the branches are easily 
broken off by the wind. 
2. A. rubrum, L. Rep Marie. A small tree with red or purple 
twigs. Leaves simple, broadly ovate, palmately 3—5-lobed or some- 
times merely serrate or cut-toothed, taper-pointed at the apex, 
rounded or heart-shaped at the base, smooth or downy, becoming 
bright red in autumn. Flowers appearing before the leaves on erect, 
clustered pedicels. Petals red or yellow, oblong or linear. Fruiting 
pedicels elongated, and drooping. Key red, smooth, wings about an 
inch long. Swamps and river banks E.* 
3. A. saccharum, Marsh (A. saccharinum, Wang.). SuGArR MAPLE. 
A large tree. Leaves simple, palmately lobed, truncate or heart- 
shaped at the base, lobes sinuate-toothed and acuminate, pale and - 
slightly downy beneath. Flowers appearing with the leaves, on 
clustered drooping pedicels. Calyx bell-shaped, fringed. Petals 
none. Keys smooth, wings about 1-1} in. long. In cold woods, 
more abundant northward. The sap of this tree is the principal 
source of maple sugar, and some forms of the tree produce the | 
curled maple and bird’s-eye maple used in cabinet-making.* 
4. A. Pseudo-Platanus, L. Sycamore Marte. Easily recognized 
by its drooping clusters of rather large green flowers, which appear 
with the leaves. Cultivated from Europe. 
5. A. platanoides, L. Norway Mapte. A large tree, with 
milky sap, which exudes from broken shoots or leafstalks in the 
spring. Cultivated from Europe ; a very desirable shade-tree. 
6. A. Negundo, L. Box Exper. A small tree. Leaves opposite, 
