63. POLYGONACE^. 341 



Agrarian region. Inferagrarian zone. 



Descends to the coast level, or nearly so, in Channel. 



Ascends to 50 or 100 yards, in Thames province. 



Range of mean annual temperature 50 — 49. 



Native. Sylvestral, Septal. Probably several other 

 counties may eventually be added to the four above men- 

 tioned, in which this species has been only recently ascer- 

 tained to occur. The late Mr. David Don informed me 

 that the alleged habitat by the Great Western Railway, 

 near Keynsham, in Somerset, was erroneous, the winged 

 variety of P. Convolvulus having there been mistaken for 

 P. dumetorum. I have seen that variety in great luxuri- 

 ance on the fresh-made embankments of railways, and also 

 in damp and shady situations; but I do not feel warranted 

 in discarding the Somerset locality for P. dumetorum, at 

 least without some more certain evidence of error on the 

 part of Mr. C. C. Babington and Mr. J. A. Hankey, who 

 are the witnesses for its accuracy. 



Polygonum Fagopyrum, Linn. 



Area (1 &c.) 



Alien. Scarcely meriting notice among British plants, 

 since it is only kept here by repeated sowings as food for 

 game. It appears to be no nearer naturalization than the 

 cereals and legumes which are sown by agriculturalists 

 year after year, without acquiring any permanent habi- 

 tats. I do not understand upon what principle botanists 

 proceed, who include this among plants " naturalized " in 

 Britain, and still exclude barley and beans from the same 

 category. 



