340 63. POLYGONACE.E. 



they all belong to P. Raii, and it has not appeared worth 

 while to indicate them for P. maritimum in the formula 

 above. Still, the ascertained existence of this species in 

 one spot on our own coast, as well as in the Channel Is- 

 lands, may be considered to suggest a probability of its 

 occurrence elsewhere on the southern coast of England ; 

 although it is too easily injured by frost to become well 

 established in our island, except in very favourable situa- 

 tions. 



941. Polygonum Convolvulus, Linn. 



Area general. 



South limit in Cornwall, Isle of Wight, Kent. 



North limit in Orkney, Hebrides, Sutherland. 



Estimate of provinces 18. Estimate of counties 81. 



Latitude 50 — 60. British type of distribution. 



Agrarian region. Inferagrarian — Superagrarian zones. 



Descends to the coast level, in the Peninsula. 



Ascends to 350 yards, in the East Highlands. 



Range of mean annual temperature 52 — 43. 



Native. Agrestal. Not enumerated among the Shet- 

 land plants by Edmondston ; and likely enough only an 

 agricultural introduction at the elevation indicated for the 

 upper limit in the Highlands. 



942. Polygonum dumetorum, Linn. >** '^-'^/.^/>a 



Area 1 2 3. 



South limit in Somerset, Sussex, ? 



North limit in Herts, Surrey, .? 



Estimate of provinces — ? Estimate of counties 

 Latitude 50 — 52. English type of distribution. 



