FOR VICTORIAN INDUSTRIAL CULTURE. 



199 



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

 sence of much yellowish pigment in the seed-shell as 

 indicating a good medicinal Rhubarb-plant. As much as 

 five lbs. of the dried drug are obtained from a single plant, 

 several years old. An important orange-red crystalline 

 substance, Emodin, allied to Crysopha,nic acid, occurs in 

 genuine Rhubarb. 



Rheum officinale, Baillon.* 



Western China and Eastern Thibet on the high tableland. 

 It furnishes the most of the true Turkey Rhubarb, not merely 

 from the root, but also from the woody stem. Suited for our 

 Alps. 



Rheum Rhaponticum, Linne. 



From the Yolga to Central Asia. This species together with 

 R. 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 culinary purposes. 

 Rhubarb-leaves can also be used in the manner of Spinage. 

 R. 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. 



Rhododendron maximum, Linne. 



North-East America, Attains a height of twenty feet. 

 Irrespective of its being a fine acquisition for any garden- 

 copses, this bush seems of industrial importance, because Mr. 

 C. Forster asserts that the wood of this and the allied 

 Kalmia latifolia (L.) is equalled only by the best boxwood. 

 This may give a clue to other substitutes for that scarce com- 

 modity, needed so extensively by the wood-engraver. 



Rhus caustica, Hooker and Arnott. 



Chili, where it is called the Litre. A small or middle-sized 

 tree, the very hard wood of which is used for wheel-teeth, 

 axletrees and select furniture. The plant seems neither 

 caustic nor otherwise poisonous (Dr. Philippi). 



Rhus copallina, Linn6. 



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, Linne.* 



The Tanner's Sumach. Countries around the Mediterranean 

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

 powder, forms the Sumach of commerce. Many localities in 

 our colony are particularly well adapted for the growth of 



