97 



those of the central ridge) (cf. Fig. 6, p. 5, in Warming's Om 

 Grönlands Vegetation). According to Lidforss, chlorophyll 

 grains occur in the upper epidermis. The stomata occur only 

 beneath the hairs on the lower surface, and are arranged 

 obliquely and project slightly. The palisade-cells occur in 

 3—4 layers and are slightly oblique; length (at most) about 

 60 fx. 



Fig. 13. Loiseleuria procumbens. 



The leaf. 1, Transverse section. 2, Stoma. 3, The epidermis of the outer surface. 

 Л/бг, Membrane. Л, Lumen. (/, Greenland: Tugtokortok.) (H.E. P.) 



The spongy tissue consists of ordinary, slightly-branching 

 parenchymatous cells, fairly thick-walled, and most developed 

 in a vertical direction; it has large intercellular spaces, which 

 also occur below the vascular bundle in the central ridge on 

 the lower surface. Stereom slightly developed. 



The stem. The primary cortex (Tedin, 1892, p. 75) within 

 the epidermal layer varies in thickness and consists of large, 



XXXVI. 7 



