79. HYDROCHARIDACi:^. 473 



500 to 700 yards, in the Highland provinces ; descending 

 thence occasionally within the limits of cereal cultivation. 



(ec ^^/^>^^,^1107. HVDROCHARIS MORSUS-RAN^, Linn. 



Area 123456|^89 10 11** [14]. 



South limit in Devon, Dorset, Sussex, Kent. 



North limit in Northumberland, York, Chester. 



Estimate of provinces 11. Estimate of counties 30. 



Latitude 50 — 55. English type of distribution. 



Agrarian region. Inferagrarian — Midagrarian zones. 



Descends to the coast level, in the Peninsula. 



Ascends to 100 yards, more or less, in England. 



Range of mean annual temperature 51 — 47. 



Native. Lacustral. As this species occurs in the 

 counties of Caermarthen, Salop, and Chester, there ap- 

 pears a probability of its existence also in one or more of 

 the counties of North Wales, sufficient to warrant the ad- 

 dition of that province to the estimated census. 



1108. Stratiotes ALOiDEs, Linv. 



Area * * (3) 4 * * * 8 9 10 (11 * * 14 15). 



South limit in Suffolk, Northampton. 



North limit in York, Lancaster. 



Estimate of provinces 4. Estimate of counties 10. 



Latitude 52 — 54. Germanic (?) type of distribution. 



Agrarian region. Inferagrarian — Midagrarian zones. 



Descends to the coast level, in the province of Ouse, 



Ascends to 100 yards, less or more, in England. 



Range of mean annual temperature 49 — 47. 



Native. Lacustral. Altliough now found in twice the 



