1836.] Boyle's Botany, $c. of the Himalayas and Cashmere. 419 



" Convolvulus Scammonia, of which the dried resinous juice forms 

 scammony, sukmoonya of the Arabs, is chiefly produced near Smyrna 

 and Aleppo ; but only inferior kinds find their way to India, though 

 there is little doubt that it might be produced of the best quality in 

 Northern India. The Jalap exported from Vera Cruz was supposed 

 to be produced in that neighbourhood, or in that of Xalapa, by Ipo- 

 moea macrorhiza of Michaux. But it was known to Humboldt (New 

 Spain, vol. iii. p. 36), and also to Dr. Coxe (v. Thomson. Elem. of 

 Mat. Med. ii. p. 289), to be the produce of a different plant. The lat- 

 ter calls it 7. Jalapa, and the former says, { that the true Purga de 

 Xalapa delights only in a temperate climate, or rather an almost 

 cold one, in shaded valleys, and on the slope of mountains.' The 

 true plant has been fully described by Professor Don, in a paper read 

 before the Linnean Society, from specimens grown from seeds sent by 

 Dr. Schiede, which he procured from Chiconquiera, on the eastern 

 declivity of the Mexican Andes, at an elevation of 6,000 feet. Mr. Don 

 retains for this the name /. Jalapa, instead of Schiedeana and Purga, 

 given it by Zuccarini and Wenderoth. The discovery of the true loca- 

 lity is important, as shewing that the Jalap requires a cool climate, 

 and may no doubt therefore be cultivated in the Himalayas." Page. 308. 



" The genus Rheum, or Rhubarb, so important in commercial point 

 of view, is more interesting than any other in its geographical distri- 

 bution. R. Rhaponticum is found in several parts of Russia, on the 

 shores of the Bosphorus and of the Caspian Sea, eastwards in Siberia, 

 and the lower mountains of the Altai Range : R. sihericum and undu- 

 latum of Pallas are considered by Ledebour to be only varieties of this. 

 R. leucorhizum (nanum Sievers) is also found in the Altai mountains 

 and the deserts of the Kirghis. Neither of these afford the rhubarb of 

 commerce, which is not found within the Russian territories, but well 

 known to be brought by the Chinese to the Russian frontier town of 

 Kiakhta, according to the treaty formed between these powers in 1772. 

 The Chinese obtain the rhubarb produced in China Proper, from that 

 part of the province of Shensee, now called Kansu, situated between 

 N. lat. 35° and 40°. But the best, according to the Missionaries, who 

 say it is called Tai-hoang, in the province of Setchuen, from the moun- 

 tains called Sue-chan, or of snow, which extend from N. lat. 26° to 

 33°, and from about 100° to 105° of E. longitude. That from the lat- 

 ter province probably forms much of what is called China rhubarb : 

 the Missionaries met large quantities of it brought down in the months 

 of October and November. That from Kansu may afford some of 

 what is called Russian rhubarb; but both Pallas and Rehman have 

 ascertained that the greater portion, if not the whole of this, is obtain- 

 ed in April and May ? from the clefts of rocks in high and arid moun- 



