S22 Select Plants for Industrial Culture 



Rheum palmatum, Linn<.* 



From insular to alpine North-Eastern Asia. Attains a height of 

 9 feet. A variety from the Tangut-country of Mongolia or North- 

 Thibet, found by Col. Przewvalski, yields an excellent medicinal root, 

 known as the Kiakhta- or Khansu-Rhubarb (Maximowicz) indeed 

 the best Russian Rhubarb. The plant is valuable also for decorative 

 effect. For medicinal culture alpine valleys with soil rich in lime 

 are needed (Sir Rob. Christison). For indications of the literature 

 on medicinal rhubarbs see among lexicographic works particularly 

 B. D. Jackson's "Vegetable Technology," London Index- Society, 

 1882. 



Rheum Rhaponticum, Linn<$. 



From the Volga to Central Asia. This species, together with R. 

 Tartaricum, 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. Propagation generally by 

 division of root. The soil for rhubarb-plants, intended to yield 

 kitchen-vegetable, must be deep and rich. 



Rhizopogon magnatum, Corda. 



Europe. One of the edible truffles sold in the markets of Middle 

 Europe, with R. rubescens, Tulasne. 



Rhododendron maximum, Linn4. 



North-Eastern America. Attains a height of about 20 feet. Irre- 

 spective 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 surpassed 

 only by the best boxwood. This may give a clue to other sub- 

 stitutes for that scarce commodity, needed so extensively by the wood- 

 engraver. 



Rhus aromatica, Aiton. 



North- America, from the Atlantic to the Pacific Ocean, northward 

 to Canada. A straggling bush. The aromatic foliage important for 

 medicinal purposes. 



Rhus caustica, Hooker and Arnott. (Lithrcea venenosa, Miers.) 



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 seemed neither caustic nor otherwise 

 poisonous (Dr. Phillippi). 



Rhus copallina, Linn<*. 



Eastern North- America, extending to Canada. A comparatively 

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

 is also obtained from this shrub. 





