367 



Rheum australe, Don.* 



(JR. Emodi, Wall. B. Wellianum, Eoyle.) 

 Hirnalaian regions up to 16,000 feet. Prom this species at 

 least a portion of the medicinal Bhubarb is obtained, most 

 likely several species furnish Ehubarb-root, and its quality 

 depends probaby much on the climatic region and the geo- 

 logic formation, in which the plant grows. Should we wish 

 to cultivate any species here for superior medicinal roots, 

 theu clearly localities in our higher and drier alpine tracts 

 should be chosen for the purpose. Hayne regards the pre- 

 sence of much yellowish pigment in the seed-shell as indi- 

 cating a good medicinal Rhubarb-plant. As much as 5 lbs. 

 of the dried drug are obtained from a single plant, several 

 years old. An important orange-red crystalline substance, 

 Emodin, allied to Crysophanic acid, occurs in geDuine 

 Rhubarb. 



Rheum Rhaponticum, L. 



From the Volga to Central Asia. This species together 

 with H. Tataricum, L. fil., R. undulatum, L., and a few others, 

 all Asiatic (one extending to Japan) provide their acidulous 

 leaf- stalks and unexpanded flower-mass for culiuary pur- 

 poses. Rhubarb leaves can also be used in the mauner of 

 Spinage. B. palmatum, L., often considered to yield the 

 best Rhubarb root, is an insular plant of North-eastern Asia, 

 but may in the alpine deserts far inland become a source of 

 the genuine root, so long ascribed to it. That is the only 

 one with deeply jagged leaves. 



Rhus copallina, L. 



North America, extending to Canada. A comparatively 

 dwarf species. This can also be used for tanning. A resin 

 for varnishes is also obtained from this shrub. 



Rhus Coriaria, L.* 



TheTanner's Sumach. Countries around the Mediterranean 

 Sea. The foliage of this shrub or small tree, reduced to 

 powder, forms the Sumach of commerce. Mauy localities 

 in our colony are particulary well adapted for the growth 

 of this bush. It is remarkably rich in Tannic acid, yielding 



