4. CRUCIFER.E. ]31 



Ascends to 1300 yards, in East Highlands. 



Range of mean annual temperature 36 — 34. 



Native. Rupestral. Very local ; being yet known only 

 fi-om the Bredalbane mountains, in Perthshire ; from Ben 

 Hope, in Sutherland; and fi-om Cairagonn, where the 

 county of Aberdeen joins Moray, or the eastern side of In- 

 verness. On Ben Lawers the altitude is about 1300 yai'ds, 

 something more and something less ; possibly descending 

 nearly to 1200 yards. But Dr. Graham reports that he saw 

 fine plants of it on another hill in the same range, probably 

 •of lower elevation than 1200 yards. The altitude of Ben 

 Hope, in Sutherland, being scarcely 1000 yards, I have 

 taken 900 as a rough guess at the altitude of the plant, 

 found by Mr. Macnab, on that hill. So far as known in a 

 wild state, this is one of oiu- most thorouglJy alpine or ai-c- 

 tic species ; and yet it seeds freely, and thus multipUes it- 

 self, in my garden in Sm'rey, where there is a pai-tial pro- 

 tection from the sun in summer, or the ground is watered 

 in drj' weather. D. incana affords a second example of 

 this easy adaptation to a different cUmate, though the dif- 

 ference of temperature is much naiTower in its ca.se. The 

 Orkney specimens belong to D. incana, not to D. rupestris. 



77. Draba incana, Linn. 



^///•/j Area ^^^^^ ^ 7^8^* 10 11 12 * * 15 16 17 18. 



^.South limit in Caernarvonshu-e and Yoifefeise, ;Z>ct^/^^ 

 North limit in Shetland, Orkney, Sutherland. 

 Estimate of provinces 8. Estimate of counties 15. 

 Latitude 53 — 61. Higliland type of distribution. 

 A. A. regions. Superagi-aiian — Superarctic zones. 

 Descends to the coast level, in North Highlands. 

 Ascends to 1 100 yaids, in East Highlands. 



