4. CRUCIFER^. 143 



but it does not appear that the author had seen specimens 

 from Mr. Don. The probabihty seems strong, that Arabis 

 hiisuta, which occm's on the mountains of Forfarshire, was 

 mistaken for the alpina or ciUata. 



92. Arabis hirsuta, Br. 



Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17. 



South limit in Devon, Isle of Wight, Kent. 



North limit in Ross-shire and Isle of Skye. 



Estimate of pi'ovinces 17. Estimate of counties 70. 



Latitude 50 — 58. British type of distribution. 



A. A. region. Inferagrarian — Midarctic zones. 



Descends to the coast level, in the Peninsula. 



Ascends to 1000 yai-ds, in East Highlands. 



Range of mean annual temperature 51 — 37. 



Native. Rupestral. Not an abundant plant, though 

 occuning in numerous localities. The actually reported 

 counties, including my own manuscript localities, amount 

 only to 45 ; so that I make a large advance to the esti- 

 mate of 70. It is possible that 60 might be nearer the 

 mark, but I cannot select 20 counties, from which this 

 plant is veiy likely to be absent. 



93. Arabis Turrita, Linn. 



Area (^ * 3 4 **-;(.******* 15). 



Alien. I have specimens fi-om walls at Oxford (Sir W. 

 C. Trevelyan), Cambridge (Rev. J. E. Leefe), and Cleish 

 (Professor Arnott) ; and it is said also to occur in Kent. 

 Allowed to be an introduced plant, and only of late ad- 

 mitted into our floras. 



