558 ACERACEAE (mAPLE FAMILY) 



§ 1, Acer proper. Disk usually present. Leaves in ours simple, palmatehj 

 lobed or cleft. 



* Flowers in terminal racemes, greenish, appearing after the leaves; stamens 



6-8. 



1. A. pennsylvdnicum. L. (Striped M., Moosewood.) Leaves 3-lobed at 

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

 also serrate; racemes drooping, loose ; petals obovate ; fruit with large diverg- 

 ing wings. — Rich woods, e. Que. to w. Ont., s. to N. E., N. Y., Great L. 

 region, and in the mts. to Ga. June. — A small and slender tree, with light 

 green bark striped with dark lines, and greenish flowers and fruit. 



2. A. spicatum Lam. (Mointain M.) Leaves downy beneath, 3(or 

 slightly 5)-lobed, coarsely serrate, the lobes taper-pointed; racemes upright, 

 dense, somewhat compound; petals linear-spatulate ; fruit with small erect or 

 divergent wings. — Moist woods, Nfd. and Lab. to Hudson B. and Man., s. to 

 N. E., N. Y., Great L. region, e. la., and in the mts. to Ga. June. — A tall 

 shrub or small tree, with reddish fruit. 



* * Flowers in nearly sessile terminal and lateral umbellate-corymbs, greenish- 



yellow, appearing with the leaves. 



3. A. saccharum Marsh. (Sugar or Rock M.) Leaves 3-5-lobed, with 

 rounded , sinuses and pointed 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. (A. saccharinum "Wang., 

 not L.) — Rich woods, especially northw. and along the mts. southw. Apr., 

 May. — A large and handsome tree. 



Var. nigrum (Michx. f.) Britton. (Black Sugar M.) Leaves green and 

 scarcely paler but usually dovmy beneath, the lobes wider, ofte:" shorter and 

 entire, the sinus at the base commonly closed; stipules often conspicuous. 

 — Rich soil, w. Que. and w. N. H., southw. and westw. ; sometimes appearing 

 distinct. 



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



preceding the leaves ; stamens 3-0. 



4. A. saccharinum L. (White or Silver M.) Leaves very deeply 6-lobed, 

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

 neath, the divisions narrow, cut-lobed and toothed; flowers on short pedicels; 

 petals none ; fruit woolly when you7ig, with large divergent wings. {A. dasy- 

 carpum P^hrh.) — River-banks. March, Apr. — A fine ornamental tree. 



5. A. rubrum L. (Red or Swamp M.) Leaves broadly ovate to suborbicular, 

 truncate or cordate at base, tomentose when young, soon glabrate, whitened 

 beneath, 8-lo cm. long ; the 3-5 acuminate lobes irregularly serrate and notched, 

 the middle one oblong at base ; petals linear-oblong ; flowers (scarlet, crimson, 

 or sometimes yellowish) on very short pedicels ; but the smooth fruit on pro- 

 longed drooping pedicels. — Swamps and wet woods, e. Que. to w. Ont., and 

 southw. Apr. — A medium-sized tree, with reddish twigs; the leaves varying 

 greatly in shape, turning bright crimson in early autumn. 



Var. Drumm6ndii (H. & A.) T. & G. Leaves large and firm, permanently 

 tomentose beneath, (A. Drummondii II. & A.) — Mo., and southw. 



Var. tridens Wood. Leaves small (5-10 cm. long), obovate, narrowed or 

 rounded and subentire or sparingly toothed below the 3 short lobes ; the middle 

 lobe broadly triangular. (A. carolinianum Britton, perhaps Walt.) — Local, 

 Mass. to Fla., Mo., and Tex. 



§ 2. NEGtiNDO (Moench) Koehne. Flowers strictly dioecious. Disk none. 

 Leaves pinnate. Negundo Moench. 



0. A. Negundo L. (Box Elder.) Leaflets 3-5 (-9), smoothish when old, 

 very veiny, ovate, pointed, toothed: petals none; fruit smooth, with large 



