152 KEY AND FLORA 



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.* 



2. A. saccharinum L. WHITE MAPLE, RIVER MAPLE. A tali 

 tree with the main branches slender and rather erect. Leaves very 

 deeply 5-lobeu, 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. 



3. A. rubrdm 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. Fruiting 

 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, 1-1 1 in. long. 

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



60. HIPPOCASTANACEJE. BUCKEYE FAMILY 



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

 compound. Mowers 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-celled, leathery cap- 

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



