Frangula californica
Credits
Article from Bean's Trees and Shrubs Hardy in the British Isles
Recommended citation
'Frangula californica' from the website Trees and Shrubs Online (treesandshrubsonline.
Infraspecifics
An evergreen bush, ultimately 10 or 15 ft high; young shoots downy the first season. Leaves oblong or oval, mostly rounded at the base, rounded or broadly pointed at the apex, minutely or not at all toothed, 1 to 4 in. long, about half as wide, glabrous above, downy on the veins beneath, veins parallel, usually in eight to twelve pairs; stalk 1⁄6 to 5⁄8 in. long, downy at first, glabrous the second season. Flowers in downy, short-stalked umbels. Fruits 1⁄4 in. across, dark purple, globose.
Native of western N. America, from Oregon southwards. With some affinity to F. purshiana in the stalked flower-clusters, this is easily distinguished by its dwarfer, purely shrubby habit, its evergreen foliage, and more globose fruits.
var. oleifolia Hook.
This has smaller, narrower leaves, oblong-ovate, 11⁄4 to 21⁄2 in. long, 1⁄2 to 1 in. wide, uniformly toothed. There are, no doubt, forms intermediate between this and the type.subsp. tomentella (Benth.) C. B. Wolf R. tomentella Benth.; R. californica var. tomentella (Benth.) Brewer & Watson – A very distinct form, the undersurface of the leaves being covered with a close, velvety, yellowish or greyish felt; young shoots and leaf-stalks the same.Other subspecies are described by C. B. Wolf in Rancho Santa Ana Bot. Gard. Mon., Vol. 1 (1938), pp. 64–70.All these buckthorns are interesting evergreens, and have in their bark aperient properties identical with those alluded to under R. purshiana; they help to meet the demand for the Cascara Sagrada drug (see R. purshiana).