404 FOREST TREES OF THE PACIFIC SLOPE. 



Cascara Sagrada." 

 Rhamnus purshiana De Candolle. 



DISTINGUISHING CHARACTERISTICS. 



Cascara sagrada varies in size and form in different parts of its wide range, 

 where it occurs in dry or moist soils, in the open or crowded in a shady forest 

 of other large trees. In moist rich soils of the north coast region, forest-grown 

 trees are from 20 to 30 feet high, with a straight, smoothish, ashy gray, or 

 sometimes brownish, trunk from 6 to 15 inches through, and a narrow open 

 crown which has only a few branches standing out straight from the undivided 

 bole ; occasionally somewhat taller ; in open places, with a very short trunk 

 from 20 to 30 inches in diameter, giving off very large, upright limbs. Farther 

 south, in poor, dry soils of open situations, usually a slend«r-stemmed & shrub 

 in dense clumps from 3 to 6 feet high; sometimes bent to the ground. Mature 

 twigs of the season are smooth or slightly and minutely downy, and usually 

 dull reddish brown. 



Mature leaves (fig. 192) in its northern and moister range are commonly 

 thin, large, prominently veiny, with sparse, very minute hairs above and 

 beneath on the larger veins and on the leaf stems ; they are shed regularly in 

 autumn. In its drier, southern distribution to and through central California, 

 mature leaves (fig. 193) are smaller, thicker, and somewhat leathery; the 

 hairiness is decidedly more pronounced, and the veins are smaller but con- 

 spicuously connected in a network : foliage of this type often persists more or 

 less during late autumn or winter. Seen separately, the two extreme forms 

 almost appear to be distinct species, but shade, soil, and atmospheric moisture 

 seem to account for distinctive characters of the northern form, while exposure, 

 dry soils, and dryness of atmosphere seem to account for the smaller, hairier, 

 thicker-leafed southern form, which, moreover, is connected with the northern 

 one by intermediate forms. Flowers, fruits, and seeds of both forms are 

 essentially alike. 



There is good reason, however, for separating from the thicker-leafed form 

 one which inhabits southern California (sometimes the central part) and 

 extends into Arizona and New Mexico. It is Rhamnus purshiana tomentella 

 (Gray) Brandegee, distinguished by the dense coating of whitish down on the 

 twigs and lower sides of the usually narrow leaves ; a wide-leafed form of this 

 variety has been found, c however, in Lake and Colusa counties, Cal. 



Mature fruit (figs. 192, 193) smooth and black (previously red) with juicy, 

 rather thin, sweetish pulp, which contains 2 or 3 hard, smooth, olive-green seeds. 

 When there are two seeds they are flat on one side like a coffee grain, and 

 when three they are triangular ; bottom end of seeds notched and top end 

 rounded.** Wood, pale yellowish brown, with faint tinge of red ; moderately 

 heavy and soft ; firm but brittle, rather coarse-grained ; layer of whitish sap- 

 wood thin in forest-grown trees, but thick in those grown in the open. Of no 

 economic use. 



"Also called bearberry, bearwood, coffeeberry, coffee-tree, bitter-bark, wahoo, and 

 shittimwood. 



b In the northern part, especially of the lower west slope of the Sierras, occurs what 

 is here considered a form of this species, with very slender, wand-like stems, clear red 

 twigs, and thinnish, narrow, sharply pointed leaves. It has been described as a distinct 

 species (Rhamnus rubra Greene, Pittonia, I, 68, 160) and deserves further careful study 

 in the field. 



c Discovered first by Prof. T. S. Brandegee. 



•* See dissemination of seeds under Rhamnus, p. 401. 



