ACERACE^. 61 



Banks of streams. Can. to Geor. April, May. — A tree 30 — 50 feet liigh, af- 

 fording a sweet sap. Leaves on long petioles, nearly smooth when old. Flowers 

 greenish-yellow or purplish, usually about 5 together. Pedicels of the fruit 

 about an inch long. Silver-leaved Maple. White Majjle. 



3. A, barbatum Mich.: leaves ovate-cordate, with 3 short lobes, un- 

 equally serrate, glaucous beneath and pubescent on the nerves ; corymbs 

 sessile ; peduncles hairy ; those of the sterile flowers branched, of the fer- 

 tile simple ; calyx bearded within ; fruit smooth ; wings erect. A. Caro- 

 liniamim Walt. 



Cedar swamps. N. J. to Car. Pursh. April. — A small tree. Leaves small. 

 Flowers pale green. Calyx densely bearded within. Hairy Maple. 



4. A. saccharinum Linn. : leaves palmately 3 — 5-lobed, subcordate at 

 base, petioled, glaucous beneath ; sinuses obtuse ; lobes acuminate ; pe- 

 duncles corymbose, loose, nodding, hairy ; fruit glabrous ; wings divergent. 



Woods. Can. to Geor. W. to Miss. April.— A tree 50—80 feet high. 

 Leaves deep green and smooth above. Flowers yellowish, on long filiform pe- 

 duncles. Petioles smooth. Valuable for its timber and for the sugar obtained 

 from its sap. * Common Sugar Maple. Hard Maple. 



5. A. 7iigrum Mich. : leaves palmately 5-lobed, cordate, with the sinus 

 closed, pubescent beneath ; lobes divaricate, sinuate-dentate ; flowers on 

 long slender peduncles, corymbed ; fruit glabrous, turgid at base ; wings 

 diverging. A. saccharinum var. nigrum Torr. tf' Gr. 



Woods, on hill-sides. Ver. to Car. April. — A large tree. Flowers yellowish. 

 Petioles pubesce]|t. BlcLck Sugar Maple. 



** Mowers in racemes. 



6. A. striatuvi Mich. : leaves with 3 acuminate lobes, rounded at the 

 base, acutely dentate, somewhat pubescent ; racemes simple, pendulous ; 

 petals oval ; fruit smooth ; wings large, somewhat diverging. A. Pennsyl- 

 vanicum Linn. 



Shady rocks. Can. to Geor. (Not south of the Highlands in N. Y. Torr.) 

 May. — A shrub or small tree 10 — 15 feet high ; trunk beautifully striate. Leaves 

 rarely undivided. Flowers large, greenish-yellow, 10 — 12 in a raceme. 



Striped Maple. Moose Wood. 



1. A. spicatum Linn.: leaves small, 3 — 5-lobed, acute, dentate, cordate, 

 pubescent beneath ; racemes spikeform, erect ; petals linear ; fruit smooth ; 

 wings somewhat diverging. A. montanum Ait. 



Rocky hills. Can. to Geor. May. — Shrub 8-— 12 feet high. Flowers green- 

 ish, small, in racemes 2 or 3 inches long. Mountain Maple. 



2. NEGUNDO. D. C. Box Elder. 



Flowers dioecious. Calyx minute, unequally 4 — 5-toothed. 

 Petals none. Antlieis 4 — 5, linear, sessile. 



N. fraxinifolium Nutt. : leaves ternate, or pinnate by fives ; leafets 

 rhomboid-oval or oval-lanceolate, acuminate, unequally and coarsely den- 

 tate ; flowers dioecious, in simple pendulous racemes. Acer Negundo Linn. 

 Mich. ■ ^ 



Low wet grounds. Can. to Geor. W. to the Rocky Mountains. April. — A tree 

 15 — ^20 feet higli, with a smooth yellowish-green bark. Leaves mostly ternate. 

 Flowers yellowish-green, pendulous. Ash-leaved Maple. Box Elder. 



