ACERACE^E 699 



Acer rubrum var. tridens Wood. Red Maple. 

 Acer carolinianum Britt. not Walt. 



Leaves obovate, usually narrowed from above the middle to the rounded or rarely cune- 

 ate base, 3-lobed at apex, with acute or acuminate erect or slightly spreading lobes, simple 

 or furnished with short lateral secondary lobes, remotely serrate except toward the base, with 



Fig. 630 



incurved glandular teeth, and often ovate by the suppression of the lateral lobes and acute 

 or acuminate, thick and firm in texture, glaucous and usually pubescent or rarely tomentose 

 or tomentulose below, 2'-3' long and 1|'-2|' wide; petioles slender, glabrous or pubescent. 

 Flowers sometimes tawny yellow. Fruit usually much smaller and rarely also yellow. 



Distribution. Usually with the species; Massachusetts and central New York, south- 

 ward usually in the coast region and the middle districts to western Florida, along the 

 Gulf coast to the valley of the Trinity River, Texas, and through western Louisiana, and* 

 Arkansas to northeastern Mississippi, southern Missouri, western Tennessee and Kentucky 

 and southern Illinois; in North Carolina occasionally ascending on the Appalachian Moun- 

 tains to altitudes of 3000; often the prevailing Red Maple in southern Missouri and 

 northwestern Louisiana; in the swamps of western Florida and southwestern Georgia the 

 form with leaves densely tomentose below and pubescent petioles prevails. 



13. Acer Negundo L. Box Elder. Ash-leaved Maple. 



Leaves usually 3, rarely 5-7-foliolate, with a slender glabrous petiole 2'-3' in length, 

 the enlarged base often furnished with a minute rim of deciduous white hairs, and in falling 

 leaving a large conspicuous scar surrounding the stem; leaflets ovate to elliptic or obovate, 

 acuminate, and often long-pointed at apex, rounded or cuneate and often unsymmetrical 

 at base, coarsely and irregularly serrate usually only above the middle or nearly entire, and 

 occasionally slightly and irregularly lobulate; when they unfold more or less hoary-tomen- 

 tose below and slightly pubescent above, and at maturity thin, light green, paler on the 

 lower than on the upper surface, glabrous above, villose-pubescent along the under side of 

 the midrib and veins, often furnished with conspicuous tufts of axillary hairs, otherwise 

 glabrous or slightly pubescent below, 2|'-4' long, and 1|'-2|' wide, on slender glabrous 

 petiolules, that of the terminal leaflet f '-!' long and much longer than those of the smaller 

 lateral leaflets. Flowers on slender glabrous or rarely hairy pedicels, minute, apetalous, 

 yellow-green, the staminate and pistillate on separate trees, expanding just before or with 

 the leaves from buds developed in the axils of the last leaves of the previous year, the stami- 

 nate fascicled, the pistillate in narrow drooping racemes, sometimes furnished near the 



