30 



Knud Jessen. 



quantity was, however, present. During summer only a very 

 small amount of fat occurs; during autumn the quantity 

 increases; a maximum is reached about the middle of Fe- 

 bruary, then the amount begins to decrease. 



For the structure of the flowering axis the reader 

 is referred to Hollstein. 



The leaves, which are usually tripartite, are covered 

 with a dense felt of white hairs on the lower surface; the 



Fig. 10. Potentilla nivea. 



A, Transverse section of a leaf, a few of the cells of the upper epidermis 

 have mucilaginous inner walls, -ß, Stoma on the lower surface of the leaf ; 

 it projects slightly. C, Epidermis of the upper surface of the leaf and D, 

 epidermis of the lower surface. E, Section of the spongy parenchyma 

 of the leaf parallel to the surface. F, Stalkedfgland from the upper sur- 

 face of the leaf. Kongsvold in Norway. (A, Б, C, D, E, F '«/i). 



upper surface is glabrous or may sometimes be more or less 

 hairy. Fig. 10, F shows a glandular hair. Such hairs were 

 found, both on the leaves from Norway, and on leaves of 

 plants in the Herbarium of the Botanical Museum in Copen- 

 hagen gathered on Danmarks in East Greenland (Hartz), 

 at King Point in Arctic America (determined by Dr. Osten- 

 feld), in the Tyrol (Huter) and in the Altai. The glandular hairs 

 are found on both leaf-surfaces though not in great quantity. 

 There is the more reason for emphasizing this fact as Wolf 



