263 



upon the rest of the leaf-blade they are arranged in groups or 

 rows and are always accompanied by short cells with undulating 

 walls. Stomata are also found (very sparsely) along the margins 

 of the leaf-stalk, accompanied by cells with undulating walls. 



В 



Fig. 14. Saxifruga groenlandica. 



A, Transverse section of leaf. B. Spongy parenchyma from just below the epidermis (,^li). 



All the stomata have their apertures parallel with the longitu- 

 dinal axis of the leaf. 



The epidermis of the lower surface (Fig. 1 3 С and I) ; Fig. 1 5 C) 

 closely resembles that of the upper, only that the stomata, and 

 the cells with undulating walls connected with them, are less 

 numerous; the large-celled groups of hair-producing cells are more 

 numerous than upon the upper side. Only glandular hairs occur. 



