RHAMNUS 331 



R. CALIFORNICA, Eschscholtz. CALIFORNIAN BUCKTHORN. 



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 ; i to 4 ins. long, 

 about half as wide ; smooth above, downy on the veins beneath ; veins parallel, 

 usually in eight to twelve pairs ; stalk % to f in. long, downy at first, smooth 

 the second season. Flowers in downy, short-stalked umbels. Fruit j in. 

 across, dark purple, globose. 



Native of Western N. America, from Oregon southwards. With some 

 affinity to R. 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, Hooker, has smaller, narrower leaves, oblong-ovate, i^- to 

 2^ ins. long, \ to i in. wide, uniformly toothed. There are, no doubt, forms 

 intermediate between this and the type. 



Var. TOMENTELLA, Brewer (R. tomentella, Bentham}. ^ very distinct 

 form, the under-surface of the leaves being covered with a close, velvety, 

 yellowish or greyish felt ; young shoots and leaf-stalks the same. 



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). 



R. CATHARTICA, Linnceus. COMMON BUCKTHORN. 



A deciduous shrub, 10 to 20 ft. high, ultimately of tree-like habit ; young- 

 shoots slender, smooth ; lateral branchlets often terminated by a thorn. 

 Leaves bright green, sometimes alternate, often opposite or sub-opposite ; oval 

 or ovate, tapered or rounded and often unequal at the base, pointed at the 

 apex ; finely toothed ; i to 2^ ins. long, half as wide ; mostly smooth, but in 

 one uncommon form (PUBESCENS) downy, especially beneath ; veins three or 

 four each side the midrib, converging towards the apex ; stalk slender, | to 

 i in. long. Flowers small, green, produced in the lower leaf-axils, and forming a 

 dense cluster at the base of the young shoot. Fruit black, about \ in. across. 



Native of Europe, W. and N. Asia, found in Britain, but not commonly. 

 A vigorous shrub, which by pruning away the lower branches may easily be 

 made to assume a tree form. It has no particular merit, although the leaves 

 die off sometimes a pleasing yellow, and a tree laden with the black fruits is 

 striking. Allied to R. davurica (q.v.}. 



R. COSTATA, Maximowicz. 



A deciduous shrub, ultimately 15 ft. high, of spreading habit ; young shoots 

 smooth, stout. Leaves opposite, ovate-oblong, pointed, tapering below to a 

 narrowly heart-shaped or cuneate base ; unevenly and shallowly toothed, 3 to 

 5 ins. long, i^ to 2^ ins. wide ; pale green on both sides, strongly rittbed, ribs 

 about twenty ; upper surface wrinkled, and furnished with a few hairs when 

 quite young ; under-surface downy, especially on the ribs ; stalk about \ in. 

 long, downy on the upper side. Flowers green, few or solitary on slender, 

 smooth stalks, f to \\ ins. long, produced at the base of the young shoots. 

 Fruit top-shaped, black, \ in. diameter, two-seeded. 



Native of Japan ; introduced in 1900. One of the handsomest of buck- 

 thorns in foliage, and belonging to the many-veined group, which includes 

 fallax and imeretina. From fallax it is distinguished by its downy leaves, and 

 from both by the long flower-stalk and strongly wrinkled upper-surface of the 

 leaf. It has also a very short leaf-stalk. 



