Rosaceæ. 



87 



The larger bundles are very prominent upon the lower sur- 

 face of the leaf which helps to support the large reniform blade. 

 These ribs consist not only of conducting tissue proper, but 

 also of rather thick-walled vein-parenchyma. True stereom 

 was not observed in the leaf. Along the veins upon both 

 sides, but especially upon the under side, such glandular 



Fig. 33. Rubus chamæmorus. 



A, Transverse section of leaf, tlie inner wall of the upper epidermis is mucilaginous. B, 

 Epidermis of the upper surface of the leaf. C, Epidermis of the lower surface of the leaf. 

 D, Section of the spongy parenchyma of the leaf parallel to the surface. (A, B, С and D 

 from Greenland.) E, Glandular hair from the lower surface of the leaf (Korway). F, 

 Longitudinal section through the central part of the pith in a runner (Denmark). G, The 

 peripheral part of an absorbent root in transverse section, the epidermis has collapsed, the 

 layer within the exodermis has strong walls (Denmark). A, B, C, D, F and G ^°°/i ; E,'"/!- 



hairs are found as shown in Fig. 33, E; scattered unicellular 

 hairs of the usual appearance are also met with. 



In the anatomy of the leaf-stalk Rub. chamæmorus differs 

 considerably from Rub. saxatilis and Rub. arcticus, which is of 

 interest as Fritsch has shown that a certain systematic 



