100 



The palisade-tissue consists of from 1 to 2 layers of cells 

 as much as 70// in height; they are longest in the specimens 

 from Härjedalen. The spongy parenchyma is relatively large 

 — comparatively larger in this species than in Loiseleuria — and 

 consists of non-branching or slightly branching cells elongated 

 in various directions and not, as is usual in Loiseleuria, 

 elongated chiefly transversely. Large intercellular spaces occur, 

 owing to the form of the leaf and to the fact that the stomata 



Es. 



Fig. 16. Phyllodoce coerulea. 



The leaf. I, 2, Transverse section. 3, Multicellular hair. 

 (Greenland: Sukkertoppen.) (E. Warming.) 



are well protected. No especial stereom nor aqueous tissue 

 occur. 



The stem. The primary cortex has a thick epidermis 

 with the same kind of hairs as on the leaf, and consists of 

 transparent cells with thick walls which occur either singly or 

 in trabeculae. The pith has a similar structure. The primary 

 cortex persists during the first and partly during the second 

 year. The secondary cortex is formed by both regular and 

 irregular cork-tissues which exhibit no point of interest. The 



