492 POLYGONACE^. 



Rheum offi^cinale Baillon is a perennial noble plant resembling the 

 Common Garden Rhubarb, but of larger size. It differs from the latter 

 in several particulars : the leaves spring from a distinct crown rising 

 some inches above the surface of the ground ; they have a sub-cylindri- 

 cal petiole, which as well as the veins of the under side of the lamina 

 is covered with a pubescence of short erect hairs. The lamina, the 

 outline of which is orbicular, cordate at the base, is shortly 5- to 7-lobed, 

 with the lobes coarsely and irregularly dentate ; it attains 4 to 4^ feet 

 in length and rather more in breadth. The first leaves in spring display 

 before expanding the peculiar metallic red hue of copper. 



The plant was discovered in South-eastern Tibet, where it is said to 

 be often cultivated for the sake of its medicinal root ; but it is supposed 

 to grow in various parts of Western and North-western China, whence 

 the supplies of rhubarb are derived. It was obtained by the French 

 missionaries about the year 1867 for Dabry, French Consul at Hankow, 

 who transmitted specimens to Dr. Soubeiran of Paris. From one of 

 these which flowered at Montmorency in 1871, a botanical description 

 was drawn up by Baillon.^ 



To what extent the rhubarb of commerce is derived from this plant 

 is not known. But that the latter may be a true source of the drug is 

 supported by the fact, that there is at least no important discrepancy 

 between it and the accounts and figures, scanty and imperfect though 

 they are, given by Chinese authors and the old Jesuit missionaries ; 

 and still more by the agreement in structure which exists between its 

 root and the Asiatic rhubarb of commerce. 



We have engaged in 1873 Mr. Rufus Usher at Bodicott (see below, 

 p. 500) to cultivate Rheum officinale, which is there admirably succeed- 

 ing ; but it must be granted that as yet the root, notwithstanding the 

 most careful preparation in drying it, is far from displaying the rich 

 yellow of the commercial drug. It is most obviously marked on the 

 other hand with the characteristic ring of stellate markings, which we 

 have constantly observed in many roots of Rheum officinale cultivated 

 by us at Clapham Common near London, as well as at Strassburg or, 

 by other observers, at Paris. 



Rhemn 'palmiatnin L., a species known as long as '1750, has always 

 been supposed to yield also rhubarb, and this has again been asserted 

 by the Russian Colonel Przewalski, who observed in 1872 and 1873 that 

 plant in the Alpine parts of Tangut round the Lake Kuku-nor, in the 

 Chinese province of Kansu, in 36°-38° North Lat. — Rheum palmatum 

 has been frequently cultivated in Russian Asia and in many parts of 

 Europe since the last century, but without producing a root agreeing 

 with Chinese rhubarb. Now, Przewalski states that from this species 

 the drug under notice is largely collected along the river Tetung-gol 

 (or Datung-ho), a tributary of the upper Hoang-ho, northward of 

 the Kuku-nor. Specimens of that root were largely brought to 

 St. Petersburg by Przewalski, but Dragendorff expressly points out 

 in his Jahresbericht for 1877 (p. 78) that it is dissimilar to true 

 rhubarb. 



^Ada7ison{a,x. 246; Association Fran^aise Lanessan's French translation of thePAa?*- 



pour Vavancement de la Science, Comptes macofjraphia, ii. (Paris, 1878) 210, gives a 



Rendus de la 1« Session, 1872. 514-529. good idea of the highly ornamental charac- 



pi. X. — The figiire which is reproduced in ter of Rheum officinale. 



