SAPINDACE.E. (SOAIMiERKY FAMILY.) 117 



3. ACER, Tcurii. Mait.k. 



Flowers polygamo-dlcrcious. Calyx colored, 5- (rarely 4 -12-) loV)ed or 

 parted. Petals either none or as many ai> the lobes of the calyx, etjual, with 

 short claws if any, inserted on the inar<;in of the lohed disk, wliich is either 

 perirjynous or hypogynous. Stamens 3-12. Ovary 2-celled, with a ])air of 

 ovules in each cell; styles 2, lon^ and slender, united only below, stij^niatic 

 down the inside. From the back of each carpel grows a wing, converting the 

 fruit into two 1 -seeded, at length sei)arable samanis or keys. Embryo vari- 

 ously coiled or folded, with large and thin cotyledons. — Trees, or sometimes 

 shrubs, with ojjposite palmately-lobed leaves, and small flowers. Pedicels not 

 jointed. (The classical name, from the Celtic ac, hard.) 



* Flowers in terminal racemes, greenish, appearim] n'',er the leaves ; stamens 6-8. 



1. A. Pennsylvanicum, L. (Striped ..Iaple.) Leaves .'5-lobed at 

 the apex, finely and sharply doubly serrate, the short lobes taper-pointed 

 and also serrate ; racemes droopinfj, loose : petals obocate ; fruit with large 

 diverging wings. — Rich woods, INIaiue to Minn., aud southward to Va., Ky., 

 and Mo. June. — A small and slender tree, with light-green bark striped 

 with dark lines, and greenish flowers and fruit. Also called Striped Dog- 

 wood and Moose- Wood. 



2. A. spic^tum, Lam. (Mountain M.) Leaves downy beneath, 3- (or 

 slightly 5-) lobed, coarsely serrate, the lobes ta])er-])ointed ; racemes upright, 

 c?f?«se, somewhat compound; petals linear-spatulate ; fruit with small erector 

 divergent wings. — ^Nloist woods, with the same range as n. 1. June. — A tall 

 shrub, forming clumps. 



* * Flowers in nearly sessile terminal and lateral itmbellate-cori/mbs, greenish- 



yellow, appearing with the leaves. 



3. A. saccharinum, Wang. (Sigar or Rock M.) Leaves 3 -5-lobed, 

 with rounded sinuses and ])ointed sparingly sinuate-toothed lobes, either heart- 

 shaped or nearly truncate at the base, whitish and smooth or a little downy on 

 the veins beneath ; flowers from terminal leaf-bearing and lateral leafless buds, 

 drooping on very slender hairy pedicels ; calyx hairy at the apex ; petals none ; 

 wings of the fruit broad, usually slightly diverging. — Rich woods, es])ecially 

 nortliward and along the mountains .soutliward. April, May. — A large and 

 handsome tree. 



Var. nigrum, Torr. & Gray. (Black Sugar-M.) Leaves scarcely paler 

 beneath, but often minutely downy, the lobes wider, often shorter and entire, 

 the sinus at the base often closed. — With the ordinary form ; quite variable, 

 sometimes appearing distinct. 



» * * Flowers in umbel-like clusters arising from separate lateral buds, and 

 much preceding the leaves; stamens 3-G. 



4. A. dasyc^rpum, Ehrh. (White or Silver M.) Leaves very deeply 

 h-lobed with the sinuses rather acute, silvery-white (and when young downy) 

 underneath, the divisions narrow, cut-lobed and toothed ; flowers (greenish- 

 yellow) on short pedicels ; petals none ; fruit icoolly when young, with large 

 divergent wings. — River-banks; most common southward and westward. 

 March - April. — A fine oruameutal tree. 



