152 KEY AND FLORA 



1-lh in. long. In cold woods, more abundant northward. The sap 

 of tills 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.* 



2. A. saccharinum L. White Maple, River Maple. 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 oif by the wind. 



3. A. rubrum L. Red Maple. 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. Fi*uiting 

 pedicels elongated and drooping. Key red, smooth, wings about an 

 inch long. Swamps and river banks E.* 



4. A. Pseudo-Platanus L. Sycamore Maple. Easily recognized 

 by its drooping clusters of rather large green flowers, which appear 

 with the leaves. Cultivated from Europe. 



5. A. platanoides L. Norway Maple. 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 Elder. A small tree. Leaves opposite, 

 pinnately 3-5-foliate ; leaflets ovate, lobed, toothed or entire, downy 

 when young. Flowers dioecious, appearing from lateral buds before 

 or with the leaves ; the staminate on long and drooping pedicels, 

 the pistillate in drooping racemes. Keys smooth, 1-H in. long. 

 River banks. Often cultivated as a quick-growing shade tree.* 



60. HIPPOCASTANACE^. Buckeye Family 



Trees or shrubs. Leaves opposite, long-petioled, palmately 

 compound. Flowers showy, somewhat monoecious, in termi- 

 nal panicles. Calyx 5-lobed, oblique. Petals 4-5, unequal. 

 Stamens 5-8, hypogynous. Pistil 1 ; ovary 3-celled, 2 ovules 

 in each cell ; style slender. Fruit a 1-3-eelled, leathery cap- 

 sule, 1-3-seeded. Seeds with a large scar.* 



