ACERACE^E 



stigmatic lobes, rudimentary in the staminate flower. Fruit often rose-colored at mid- 

 summer, green at maturity, glabrous or rarely sparingly hairy, with spreading or erect 

 wings 2'"!' long; seeds smooth, light red-brown, about \' long. 



A tree, occasionally 30-40 high, with a trunk 8'-10' in diameter, stout usually erect 

 branches, and slender glabrous bright red branchlets marked by numerous small pale 

 lenticels and nearly encircled by the narrow leaf-scars, with conspicuous bands of long pale 

 hairs in their axils. Winter-buds acute or acuminate, about -fa' long, bright red-brown, 

 with puberulous-ciliate outer scales and obovate apiculate inner scales sometimes \' long 

 when fully grown. Bark of the trunk thin, dark brown, separating on the surface into 

 plate-like scales. Wood heavy, hard, close-grained, bright brown or nearly white, with 

 thick sap wood. 



Distribution. Banks of mountain streams usually at altitudes of 5000-6000 C above 

 the sea; on the Salt River Mountains, western Wyoming; valley of the Columbia River in 

 northern Montana, southeastern Idaho (Pocatello, Oneida County), Wasatch Mountains, 

 Utah, mountains of Arizona and of southern New Mexico; on the Guadalupe Mountains, 

 western Texas, and on the Wichita Mountains, southwestern Oklahoma (G. W. Stevens) ; in 

 Coahuila; rare and local. 



Occasionally cultivated; hardy in the Arnold Arboretum. 



9. Acer nigrum Michx. Black Maple. 



Leaves generally 3 or occasionally 5-lobed, with abruptly short-pointed acute or acu- 

 minate lobes, undulate and narrowed from broad shallow sinuses and rarely furnished with 

 short lateral spreading lobules, cordate at base with a broad sinus usually more or less closed 



Fig. 625 



by the approximation or imbrication of the basal lobes, occasionally 3-lobed with a broad 

 long-acuminate nearly entire terminal lobe, and rounded or slightly cordate at base (var. 

 Palmeri Sarg.), covered below when they unfold with hoary tomentum and above with 

 caducous pale hairs, and at maturity thick and firm in texture, dull green on the upper 

 surface, yellow-green and soft-pubescent, especially along the yellow veins on the lower 

 surface, and 5 '-6' long and wide, with drooping sides; turning bright clear yellow in the 

 autumn; petioles stout, tomentose or pubescent, sometimes becoming glabrous at maturity, 

 usually pendent, 3'-5' in length, much enlarged at base, frequently nearly inclosing the 

 buds, in falling leaving narrow scars almost encircling the branchlet and furnished in their 

 axils with tufts of long pale hairs; stipules triangular and dentate or foliaceous, sessile or 

 stipitate, oblong, acute, tomentose or pubescent, sometimes slightly lobed, frequently 

 H' long. Flowers yellow, about ' long, on slender hairy pedicels 2^ '-3' long, in many- 



