THALAMIFLOR^ 105 



Hymenoptera visit the plant, it must usually be self- 

 pollinated. 



The siliculas open as in other Cruciferous plants, 

 and the seeds are blown away by the wind. 



The name Draba means acrid or blistering, from 

 the taste of the plant. 



The name Whitlow Grass refers to some former 

 remedy the plant was considered to afford for whit- 

 lows. 



Vernal Whitlow Grass is also called Faverel, 

 Whitlow Grass, Nailwort, White Blow. 



Gerard says : " It hath been taken to heale the 

 disease of the nailes called a whitlowe." 



Draba verna. — The habit of this plant is well 

 displayed in Fig. 14, where the habitat is also shown. 

 The plant is in fruit and the elliptic silicnlas are clearly 

 depicted. 



AWLWORT {Snbidaria aquatica). 



Awlwort is unique amongst the Cruciferae in 

 adopting the aquatic habit (hence aquatica). 



The Awlwort is, moreover, scarce in the British 

 Isles, occurring in the Highlands, the Lake District, 

 North Wales, and the West of Ireland. 



In the fresh-water aquatic formation Awlwort 

 occurs as a submerged plant, in lochs and tarns of a 

 highland character on siliceous rocks, where the 

 water is poor in mineral salts. It grows on the 

 shallow margins of such alpine ponds or lakes, where 



