260 



epidermal cells, and their walls are far more undulaling. The 

 groups of slomata are continued as a long and very narrow 

 stripe along — and slightly within — both the margins of the 

 leaf-stalk, and are here also accompanied by the higlily charac- 



Fig. 12. Saxifraga hypnoides. 



F, Spongy parenchyma from just below the epidermis of the leaf-blade. G. The same 



from just below the epidermis of the leaf-stalk. B, The same from midway between the 



epidermis and veins. /, Longitudinal section of leaf. K, Transverse section of leaf. 



(F, G, B, 1 and K «Vi). 



teristic small epidermal cells with undulating walls. Almost all 

 the hairs are without apical glands; they occur invariably in 

 the spaces between the groups of stomata and arise from the 

 straight-walled cells — never from those with undulating walls. 

 The structure of the epidermis of the lower surface (Fig. 11 E) 



