THE BUCKWHEAT FAMILY. 



241 



to be the only relic of the once glacial period of that 

 mountain. 



Ehubarb {Rheum palmatum andE.Emodi). Perennial plants, 

 natives of Russia, the range of the Himalaya and western 

 China. From the latter country, large quantities of the roots 

 enter Russia, from which place the best rhubarb comes to 

 this country. The roots of E. Emodi find their way to 

 Aleppo, thence to Constantinople, and from there to this 

 country, under the name of Turkey rhuharh. There is how- 

 ever, some doubt which species produces the best rhubarb, 

 the Chinese and Tartars not being willing that the plant 

 should be known. But the quality in a great measure de- 

 pends on the collecting, drying, and transport. R. palmatum 

 is much grown in this country for its roots, especially about 

 Banbury. R. Rhaponticum, a native of Western Asia, is ex- 

 tensively cultivated for its leafstalk, which is well known as a 

 culinary vegetable, R. undulatum and R. palmatum being 

 used for the same purposes, as well as made into wine and 

 preserves. 



Rhubarb contains numerous crystal bodies, in botany 

 called raphides, which by the aid of the microscope are 

 readily seen in the fresh or cooked leafstalk, having the 

 appearance of numerous needles, and said to consist of phos- 

 phate of lime, and it is supposed that the medical virtue of 

 rhubarb is in some way due to them, it being one of our 

 best purgative medicines. 



Buckwheat or Brank {Fagopyrum esculentum). This is 

 supposed to be a native of Central Asia, where it is exten- 

 sively cultivated, but it has now become widely spread in 

 most countries. It is largely cultivated in France, Holland, 

 and the United States, for its seeds, which are ground into 

 meal and made into thin cakes. In this country it is used 

 for feeding pheasants. 



Polygonum Convolvulus. This is a pest in cornfields, 

 twining round and destroying the crops. 



Monks Rhubarb (Rumex alpinus). This has been na- 

 turalized in some parts of Scotland, and with other large 



B 



