RHAMNUS 335 



opening in July ; sepals and petals five, flower-stalks downy. Fruit top-shaped, 

 in. long, black, usually three-seeded. 



Native of Western N. America ; introduced in 1891. A handsome small 

 tree, although without any beauty of blossom, forming a broad leafy head of 

 erect or spreading branches. It is allied to R. Frangula, but has more numerous 

 parallel veins in each leaf that are downy above, and differs in the distinctly 

 stalked flower- clusters, the common stalk being often j? in. or more long. 

 R. Purshiana is the source of the well-known drug, " Cascara Sagrada," one 

 of the most popular of aperient medicines. It is obtained from the bark, and 

 so great is the demand that 20,000 worth was sent from the states of Oregon 

 and Washington in 1907. The consequence is that natural supplies are being 

 rapidly used up, and it has been suggested that the cultivation of this tree in 

 the southern and western parts of the British Isles might prove profitable. 

 The bark of trees raised and grown at Kew has been proved to possess the 

 aperient quality as fully as that of wild trees. 



R. CAROLINIANA, Walter. Indian Cherry. This is nearly related to 

 R. Purshiana, and may be regarded as its E. American representative. It 

 differs from the above in having narrower, more pointed leaves, with fewer 

 (eight to ten) pairs of parallel veins. It resembles it in having stalked umbels, 

 lout the stalks are much shorter. Introduced in 1819, according to Loudon, 

 but now rarely seen, and perhaps not very hardy. It varies from a shrub to a 

 tree 30 to 40 ft. high. 



R. RUPESTRIS, ScopolL 



A deciduous shrub of low, spreading habit, from 8 to 30 ins. high ; young 

 shoots covered with fine hairs. Leaves oval, or inclined to oblong, or some- 

 times orbicular, rounded at the base, pointed or rounded at the apex ; f to 

 2 ins. long, about half as wide ; minutely or not toothed ; dull green and 

 smooth (or with the veins downy) above, greyish beneath, and finely hairy on 

 the midrib, veins, and stalk ; veins parallel, in five to eight pairs. Flowers in 

 downy, stalked umbels. Fruit at first red, then black, roundish top-shaped, 

 J in. wide, three-seeded. 



Native of S.E. Europe, inhabiting mountain regions. In habit and leaf it 

 resembles R. pumila, but is distinguished by the more hairy shoots and 

 stalked inflorescences. The latter are sometimes borne on short, lateral, leafy 

 twigs springing from the leaf-axils. 



R. SAXATILIS, Jacquin. ROCK BUCKTHORN. 



A low, spreading, deciduous shrub, rarely more than 2 ft. high ; young shoots 

 minutely downy, lateral branchlets often ending in a spine. Leaves smooth 

 or nearly so, narrowly oval, ovate or obovate, tapered at the base, often 

 bluntish at the apex, finely toothed ; \ to I in. long, \ to \ in. wide ; veins two 

 to four each side the midrib, converging towards the apex ; stalk \ in. or 

 less long. Flowers very small, greenish yellow. Fruit black, top-shaped, 

 three-seeded. 



Native of the mountains of Central and S.E. Europe ; introduced in 1752. 

 A curious dwarf or stunted shrub inhabiting rocky places, belonging to the 

 same group as tinctoria and infectoria, but distinguished by its dwarf habit and 

 smaller, smooth leaves. 



R. SPATHUL^FOLIA, Fischer. 



A deciduous shrub up to 6 ft. high, with downy shoots and narrow-oval 

 or lanceolate leaves ; f to 2^ ins. long, to f in. wide ; slenderly tapered at 

 the base and apex, finely toothed, distinctly downy on both surfaces ; veins 



