Naturalisation in Extra-Tropical Countries. 

 Rheum palmatum, Linne.* 



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

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

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

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

 the best Russian Rhubarb. Cultivation of this variety in Germany 

 on sandy moor-ground developed in the root to a large extent the 

 chrysophanic acid and emodin [Prof. Beilstein]. 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 Techno- 

 logy, London Index- Society, 1882. 



Rheum Rhaponticum. Linne. 



From the Volga 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 in their acidulous leaf -stalks and 

 unexpanded flower-mass for culinary purposes the ordinary Rhu- 

 barb, also known as "Rhapontic." Rhubarb-leaves can also be 

 used in the manner of spinage. In tropical climes this culinary 

 vegetable is available only during the cool season. Propagation 

 generally by division of root. The soil for rhubarb- plants, intended 

 to yield kitchen-vegetable, must be deep and rich. 



Rheum Ribes, Gronovius. 



Palestine, Persia, Beloochistan, from 3,000 feet upwards, on wet 

 clay-soil. The native inhabitants are very fond of the young 

 flowering shoots as food. Foliage scarlet in autumn [Dr. J. 

 Aitchison]. 



Rhizopog-on magnatum, Corda. 



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

 Europe, with R. rubescens (Tulasne). 



Rhododendron maximum, Linne. 



North-Eastern America. Attains a height of about 20 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 

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

 substitutes for that scarce commodity, needed so extensively by the 

 wood-engraver. 



