662 



TREES OF NORTH AMERICA 



Peduncles shorter than the petioles. 

 Peduncles longer than the petioles. 



2. R. Caroliniana (C). 

 3. .R. Purshiana (B, G). 



1. Rhamnus crocea, Nutt. 



Leaves persistent, elliptical, broadly ovate or subrotund, or rarely lanceolate- 

 acuminate, mucronate or rounded at the apex, acutely or often glandular-denticulate, 

 sometimes revolute, coriaceous, yellow-green and lustrous on the upper surface, paler 

 or frequently bronzed or copper color on the lower surface, glabrous or often puberu- 

 lous, especially when young, on the under surface of the midribs and petioles, ^'-3' 

 long, with prominent midribs grooved above and broad conspicuous primary veins; 

 their petioles short and stout. Flowers poly gam o-dicecious, on slender often puberu- 

 lous pedicels ^' long, in small clusters from the axils of the leaves or of small lan- 

 ceolate persistent bracts on shoots of the year; calyx 4-lobed, with acuminate lobes, 

 about \' long; petals 0; stamens shorter than the calyx, with short stout incurved 

 filaments and large ovate anthers, minute and rudimentary in the pistillate flower; 



ovary ovate, contracted into a long slender style divided above the middle into 

 2 wide-spreading acuminate stigmatic lobes, rudimentary in the staminate flower. 

 Fruit red, obovoid, slightly grooved or lobed at maturity, \' long, with thin dry flesh 

 and 1-3 nutlets; seeds broadly ovate, pointed at the apex, deeply grooved on the 

 back, and \' long, with a thin membranaceous pale chestnut-colored coat. 



A tree, occasionally 20 high, with a trunk 6'-8' in diameter, spreading rigid 

 sometimes spinescent branches, and slender branchlets yellow-green and puberulous 

 or glabrate when they first appear, becoming dark red or reddish brown and gla- 

 brous in their second season; more frequently a low densely branched shrub, with 

 stems a few feet high forming thickets of considerable extent. Winter-buds 

 obtuse, barely more than ^' long, with small puberulous apiculate imbricated scales 

 ciliate on the margins. Bark of the trunk usually fa'-\' thick, the dark gray surface 

 slightly roughened by minute tubercles. 



Distribution. Valley of the upper Sacramento River, California, southward along 

 the Sierra Nevada to about latitude 28 on the mainland and to Guadaloupe Island, 

 Lower California; usually an undershrub under the shade of trees and along the 

 borders of the forest or in sheltered ravines ; sometimes appearing in exposed situ- 

 ations on sunny hillsides in the neighborhood of streams; arborescent only in some 



