264 



EuG. Warming. 



In Minuartia groenlandica I found distinct palisade- 

 tissue on the ventral side, but in the specimen investigated 

 the leaves were, in contradistinction to those in M. verna, 

 directed decidedly outwards. The epidermis of the dorsal 

 surface was distinctly thicker than that of the ventral surface. 



Stellaria humifusa (Fig. 19). According to the transverse 

 sections shown in Fig. 19, В and C, this leaf is but shghtly 



Fig. 19. Stellaria humifusa. 

 (From East Greenland; 15. 7. 1885; P. Eberlin.) 

 A, Transverse section of leaf. B, The same, more highly magnified; 

 V, ventral surface; d, dorsal surface. C, A transverse section, the epi- 

 dermal cells are nearly equal in height, which is seen more distinctly 

 in the more highly magnified H (from the ventral surface) and J (from 

 the dorsal surface). D, The epidermis of the ventral surface, and E, 

 the underlying mesophyll-cells. F, The epidermis of the dorsal surface 

 and G the underlying mesophyll. (E. W.) 



dorsiventral, but a closer observation proves the dorsiven- 

 trality to be stronger. The epidermis of the dorsal surface 

 is but little thicker than that of the ventral surface (Fig. 19, 

 J and //), but the ventral surface has cells with decidedly 

 undulating walls (D), and is rich in stomata, while the 

 dorsal surface has elongated cells with straight sides (F). 



