97 
those of the central ridge) (cf. Fig. 6, p. 5, in Warmine’s Om 
Grönlands Vegetation). According to Livrorss, 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 y. 
Fig. 13. Loiseleuria procumbens. 
The leaf. 2, Transverse section. 2, Stoma. 3, The epidermis of the outer surface. 
Mbr, Membrane. 2, Lumen. (2, 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 (Ten, 1892, p. 75) within 
the epidermal layer varies in thickness and consists of large, 
XXXVI. 7 
