ROSACES 551 



inferior. Fruit a linear-oblong coriaceous slightly ridged angled or sulcate akene, included 

 in the persistent tube of the spindle-shaped calyx more or less deeply cleft at the apex, and 

 tipped with the elongated persistent style clothed with long white hairs. Seed solitary, 

 linear, acute, erect; hilum conspicuous lateral above the oblique base; testa membrana- 

 ceous; embryo filling the cavity of the seed; cotyledons ovate-oblong, elongated, fleshy; 

 radicle inferior. 



Cercocarpus is confined to the dry interior and mountainous regions of North America. 

 Twenty-one species, often of doubtful value, have been distinguished; seventeen are cred- 

 ited to the territory of the United States and the others to Mexico. The heavy hard brittle 

 wood of all the species makes valuable fuel and is occasionally used in the manufacture of 

 small articles for domestic and industrial use. 



The generic name, from K^PKOS and Kapwbs, refers to the peculiar long-tailed fruit. 



CONSPECTUS OF THE ARBORESCENT SPECIES OF THE UNITED STATES. 



Flowers usually in many-flowered clusters. 

 Leaves coarsely serrate above the middle. 



Leaves oval to semiorbicular or obovate, hoary-tomentose below, sinuate-dentate; 



flowers short-pedicellate. 1. C. Traskiae. 



Leaves oval to slightly obovate, green and glabrous below, denticulate with broad 



apiculate teeth; flowers long-pedicellate. 2. C. alnifolius. 



Leaves finely serrate above the middle, obovate to oval, pale and villose below; flowers 



short-pedicellate. 3. C. betuloides. 



Flowers solitary or rarely in 2 or 3-flowered clusters, nearly sessile. 



Leaves narrow-lanceolate, lance-elliptic or oblanceolate, acute at the ends, entire, pale 



or rufous below. 4. C. ledifolius. 



Leaves oblong-obovate to narrow-elliptic, entire or slightly dentate below the apex, 



villose-pubescent. 5. C. paucidentatus. 



2. Cercocarpus Traskiae Eastw. 



Leaves oval to semiorbicular or obovate, rounded or acute at apex, cuneate, rounded or 

 occasionally somewhat cordate at the narrow base, revolute on the margins, entire below, 



Fig. 507 



coarsely sinuate-dentate above the middle with slender teeth tipped with minute dark 

 glands, when they unfold covered above with soft pale hairs and below with thick hoary 

 tomentum, and at maturity coriaceous, dark green, lustrous and villose or nearly glabrous 



