376 THE KINDS OF PLANTS 



1. CARDIOSPERMUM. Balloon-vine. Heart-seed. 



Vines climbing by axillary, hook-like tendrils among flower-clusters: 

 leaves alternate, biternate, leaflets toothed: flowers dioecious, or some per- 

 fect; sepals 4, 2 of them smaller; petals 4, irregular, each with an appendage 

 at inner base; stamens 8, filaments un- 

 equal; style short, 3-cleft; ovary triangular, 

 3-celled, 1 ovule to each cavity: capsule 

 membranous, much inflated. 



C. Halicacabum, Linn. Climbing 

 or spreading herb, delicate and slender: 

 leaflets ovate-lanceolate, acute, cut and 

 toothed: flowers small, white: fruit large, 

 balloon-like, decorative; seeds black with 

 523, '524 white scar, hard, round. Cultivated. 



Acer saccharinum. Acer rubrum. Summer. 



2. ACER. Maple. Box-elder. 



Trees or shrubs, with opposite lobed or parted leaves (pinnate in box- 

 elder): flowers small and greenish or reddish, in early spring and often 

 from winter buds, in box-elder dioecious, in true maples perfect (or imperfectly 

 diclinous); calyx about 5-cleft; petals 5 or none; stamens usually 3-8: fruit 

 a samara with 2 seeds and 2 wings. Two shrubby woods maples are common 

 in some parts of the country. 



a. Maples: leaves simple, palmately lobed. 



b. Flowers from lateral winter buds, preceding the leaves: fruit 



maturing very early. 



A. saccharinum, Linn. (A. dasycdrpum, Ehrh.). While or silver maple. 

 Fig. 523. Flowers greenish, with no petals: leaves very deeply 5-lobed, 

 silvery white beneath, the narrow divisions lobed and toothed: fruit with 

 large spreading wings, downy when young. Common along streams and in 

 low grounds; much planted. There is a cut-leaved form known as Wier's 

 maple, popular as a lawn tree. Wood white. Linnaeus thought it to be the 

 sugar maple, hence his name "saccharinum." 



A. rubrum, Linn. Red, soft, or swamp maple. Fig. 524. Tree usually 

 of only medium size: flowers red, with narrow- 

 oblong petals: leaves rather small, not deeply 

 3-5-lobed, whitish beneath, the lobes serrate 

 and toothed: fruit with'nearly parallel or slightly 

 spreading wings, not downy. Low grounds. 



bb. Flowers in clusters, with the leaves, some 



or all on shoots of the season. 525. Acer saccharum. 



A. saccharum, Marsh. (A. saccharinum of some). Sugar, hard, or rocA: 

 maple. Figs. 143, 525. Flowers greenish, drooping, on long pedicels, the 

 petals none and the calyx hajry at the top: leaves bright green, firm, cordate- 

 orbicular in outline, 3-lobed and the side lobes again lobed, all lobes and 



