MAPLES 377 



teeth ending in points, the basal sinus broad and open: wings of fruit some- 

 what spreading. Commonest of maples East. 



A. nigrum, Michx. Black sugar maple. Fig. 526. Foliage dark and limp, 

 the lobes broad and shallow, little toothed and with only blunt points, the 

 basal sinus nearly or quite closed: wings of fruit nearly parallel, large. 

 Eastern Central States; by some regarded as a form of A. saccharum. 



A. plantanoides, Linn. Xorway maple. Figs. 79, 80, 157, 323-330. Flowers 

 late, in umbel-like clusters, yellowish green, large, with both sepals and 

 petals: leaves large and heavy, 3-5-lobed and much toothed, all parts ending 

 in points: fruit with wide-spreading wings. Europe. Commonly planted: 

 has milky juice. 



A. Pseudo-platanus, Linn. Sycamore maple. Tree from Europe, and 

 many varieties cultivated: leaves broad, 3-7-lobed, glabrous above, whitish 

 and downy below; lobes acute, unequally toothed: racemes terminal, droop- 

 ing; flowers yellowish-green; ovaries woolly: fruit downy, the wings rather 

 spreading. 



bbb. Flowers appearing after the leaves, in racemes: large bushes or 

 bushlike small trees in cool woods and ravines. 



A. pennsylvanicum, Linn. Striped maple. Moose-wood. Bark smooth- 

 ish, light green, striped: flowers greenish, in ter- 

 minal drooping loose racemes: leaves simple, 

 thin, 3-lobed near apex, the lobes acuminate, 

 with finely toothed margin all around: fruit 

 greenish, smooth, with large, widely diverging 

 wings. Small tree. 



A. spicatum, Lam. Mountain maple. Shrub, 526 Acer nigrum 



5-10 ft., usually forming clumps: bark green, 



not striped: flowers appearing after leaves, in dense racemes, upright, 

 compound, small, greenish: leaves slightly 3-5-lobed, coarsely serrate: fruit 

 with narrow, somewhat divergent wings. 



aa. Box-elder: leaves pinnate. 

 A. Negundo, Linn. {Negundo aceroides, Moench). Box-elder. Tree with 

 green glaucous twigs and leaf-bases covering the buds: flowers in long 

 racemes, dicecious, with 4-5-cleft calyx and no corolla, and 4-5 stamens, the 

 sterile flowers on long, slender pedicels: leaves pinnate, with 3-5 ovate- 

 pointed toothed leaflets: fruit with somewhat incurving wings. Common; 

 much planted in cold and dry regions west. 



3. jESCULUS. Horse-chestnut. Buckeye. 



Trees: leaves opposite, on long petioles, palmately compound, 5-7-folio- 

 late: flowers irregular, in a terminal panicle, some often imperfect, most of 

 them with some imperfect pistils and stamens; calyx 5-toothed; corolla 

 irregular, with 4 or 5 clawed petals; stamens 5-8, usually 7: fruit a leathery 

 capsule, smooth or spiny, 2-3-valved, each valve containing, usually, 1 seed 

 only; seed large, with shiny brown coat and a large, round, pale scar; not 

 edible. 



