24. ROSACEA. 341 



berland ; the course of the Tees, both on the Yorkshire 

 and on the Durham sides of the river ; and by the river 

 Don, in the limestone tract westward of Doncaster. In the 

 Scottish locahty, the Falls of Clyde, it has probably been 

 planted. Wastdale Screes may perhaps be considered 

 within the inferarctic zone ; but some of the places in 

 which it is found, by the Tees, must be within the supera- 

 graiian zone ; and possibly others even so low as the mid- 

 agi'arian, especially should the banks of Don, near Don- 

 caster, prove a true locahty. I am unprepared to make any 

 \ery satisfactory estimate of the altitude and temperature. 



326. POTENTILLA RUPESTRIS, Linn. 



Area * * ji^ ^^ * * 7. 



South and Noi-th limits in Montgomeryshire. 



Estimate of provinces 1.. Estimate of counties 1. 



Latitude 52 — 53. - Engiioh tj-jje of distribution. - -^ ^'*'^ ^^' 



Agrarian region. Midagrarian zone .'' 



Descends, and Ascends, to 150 — 250 yards. 



Range of mean annual temperature, say 47 — 46. 



Native. Rupestral. Not having seen the locality of 

 this plant, which is appai'ently limited to one hill in Wales, 

 I am obliged to enter the range of altitude and temperature 

 by an estimate founded on infonnation given to me by the 

 late J. E. Bowman, to the following effect : " This very 

 local plant is distributed, sometimes in groups very pro- 

 fusely, on the western face of the Breidden HUl ; occu- 

 pying the middle zone, disajjpearing at 600 or 700 feet, 

 and not descending near the base. It occurs again on the 

 vexy steep northern side, where it comes lower down. Yet 

 it grows verj' well, and is produced from seed, in a waim 

 garden." Even in Surrey, also, in very diy and loose 



