40 



Knud Jessen. 



The spongy parenchyma consists of shortly branched cells 

 and has a loose structure (Fig. 15, A, E). Slit-like lacunæ are 

 often found upon the dorsal side of the leaf. Stereom is absent. 



Fig. 15. Potentilla emarginata. 

 A, Fragment of a transverse section of a leaf ; k, a glandular hair. B, Epidermis from the 

 lower leaf-surface with 2 stomata and a glandular hair k. C Epidermis of the upper 

 leaf-surface. D, Epidermis of the lower leaf-surface. E, Section of the spongy paren- 

 chyma of the leaf. F, Transverse section of an absorbent root ; ep, the collapsed epider- 

 mis ; ex, exodermis ; h, fungal hyphse, which partly forms balls in the cortical cells and 

 partly fills out the intercellular spaces; s, the leptome-groups of the central cylinder. A, 

 From Lille Snenæs; B, C, D, E and F from Upernivik (A, B, C, D. E and F about "*>/,). 



