558 ACERACEAE (MAPLE FAMILY) 



§ 1. Acer proper. Disk usually present. Leaves in ours simple^ palmatel^ 

 lobed or cleft. 



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



6-8. 



1. A. pennsylv^nicum 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 winj^s.— Rich woods, e. Que. to w. Dnt., 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. (Mountain 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 nearhj sessile terminal and lateral umbellate-corymbs, greenish" 



yellow, appearing with the leaves. 



3. A. sdccharum Marsh. (Sugar or Rock M.) Leaves 3-6-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 north w. 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, often 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 3-6. 



4. A. saccharinum L. (White or Silver M.) Leaves very deeply 5-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 young, with large divergent wings. (^A. dasy- 

 carpum Ehrh.) — River-banks. March, Apr. — A fine ornamental tree. 



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

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

 beneath, 8-15 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. (J.. Brummondii H. & 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. NEGtJNDO (Moench) Koehne. Flowers strictly dioecious. Disk none. 

 Leaves pinnate. Negundo Moench. 



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

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



