Caryophjilaceæ. 



259 



О. Gallöe, а. Mentz, Knud Jessen and Mathiesen. See 

 also Th. Holm; Lazniewski may also be consulted. 



The foliage-leaves are dorsiventral or almost isolateral 

 (central). 



The difference in the leaves is evidently connected with 

 their breadth and the direction of their growth. In the broad- 

 leaved species (the Melandrium-ijpe) dorsiventrality prevails 

 with palisade-tissue on the ventral side; see for instance 



Fig. 14. Viscaria alpina. 

 (West Greenland; 24.7.1887; Lytzen.) 

 A, In the transverse section of the leaf is seen on the dorsal side a 

 large lacuna, and on the ventral side a distinct palisade-tissue (sa) ; 

 the crosses (xx) indicate cells with crystals of calcium oxalate; round 

 the vascular bundles are sheaths. B, Transverse section of a leaf. 

 С and D, Details from ventral and dorsal surfaces, more highly magni- 

 fied. The epidermis of the ventral surface is distinctly higher than 

 that of the dorsal surface; there are stomata on both surfaces. Pores 

 are seen in the lateral walls of the epidermal cells. E and F, Epidermis 

 of ventral and dorsal surfaces; the walls are highly poröse. G and H, 

 Section through the palisade-tissue and the spongy-tissue. (E. W.) 



Viscaria alpina (Fig. 14 and the explanation of the figure); 

 here the dorsiventrality is expressed by the fact that on 

 the ventral side there are two layers of palisade-cells, while on 

 the dorsal side there is a spongy-tissue of rounded cells, with 



