Flora Medica

POLYGONACEJE.%* This genus is very important, on account of the officinal rhubarbbeing produced by some of the species. It is, however, not a littlecurious that up to the present time no one should have ascertained withcertainty from which of the many known species any of that which findsitsway to Europe through Turkey and Russia, is really obtained.The species inhabit the plains of Tartary, the wastes of Siberia, andthe lofty mountains cutting off India from the high and cold table landto the north. They are all similar in their flowers, but their leaves,particularly the leafstalks, afford excellent marks of distinction whenthe plants are wild. In the' gardens they hybridise so readily, that ithardly possible to say to which of the wild types the many cultivatedsorts are referable. In the following account, I have includedevery species with which I am acquainted, or of which an account canbe found in books. There is some confusion in the synonymy, whichI have endeavoured to adjust; but the genus requires all the care of askilful monographist. Guibourt seems to me to have studied thesubject with more attention than any one ;and I have accordinglyincorporated his opinions in the following short history of the species.It will be seen that the whole subject is involved in the greatestobscurity and : it is probable that Professor isRoyle correct in hisopinion that the officinal drug, obtained in the heart of Thibet, whitherno botanist has ever penetrated,is the produce of some species stillunknown. I extract the following account of the origin of officinalrhubarb from this gentleman's excellent Illustrations of the Botany ofthe Himalaya Mountains, " S/-c.The rhubarb of commerce is well knownto be brought by the Chinese to the Russian frontier town of Kiachta,according to the treaty formed between those powers in 1772. TheChinese obtain the rhubarb produced in China Proper, from that partof the province of Shensee now called Kansu, situated between N.35 and 40 ;but the best, according to the missionaries, sayis called Tai-hoang, in the province of Letchuen, from the mountainscalled Sue-chan, or of snow, which extend from N. lat. 26 to 33and from about 100 to 105 of E. longitude. That from the latterprovince probably forms much of what is called China rhubarb : themissionaries met large quantities of it, brought down in the months ofOctober and November. That from Kansu may afford some of whatis called Russian rhubarb ;but both Pallas and Rehman have ascertainedthat the greater portion, if not the whole of this, is obtained inApril and May from the clefts of rocks in high and arid mountainssurrounding lake Kokonor. Bell also learnt that it was the produce ofMongolia, and Marco Polo of Succuir, in Tanguth. Dr. Rehmanascertained that the trade is in the hands of one Bucharian family, whofarm the monopoly from the Chinese government, and reside at Si-ning,a Chinese town on the very frontiers of Tibet, 3000 verstes from Kiachta,and 20 days journey from Kian-sin and Schan-sin, Tangutian towns,where the Bucharians go to purchase rhubarb. This would bring therhubarb country within 95 of E. long, in 35 of N. latitude, that is inthe heart of Thibet.732. R. Emodi Wallich MSS. Cat. herb. ind. No. 1727.Hooker in Bot. mag. t. 3508. R. australe Donprodr.fi. nep. 75. ;id. in Sweet Fl. Gard. t. 269. Mountains of Gossain Than,Kamaon.354