116 



The upper and lower epidermis are thin-walled throughout 

 and have no thick cuticle or cuticularized layer. The outer 

 walls are, however, coloured yellow by chlor-zinc-iodine. The 



Fig. 28. Arctostaphylos alpina. 



1 — 4, The leaf. Ei, The large air-cavities formed by the epidermis of the lower surface 

 having separated from the mesophyll; some of the large cells of this epidermis may also 

 be seen. 5, shews Ьолт the new epidermis of the stem is formed. (Finmark: Tromsö: 



Jan. 5.) (H. E. P.) 



cells of the upper epidermis have slightly undulating lateral 

 walls while those of the lower are strongly undulating. Hairs 

 are absent. The stomata are confined to the lower surface and 



