Caryophyllaceæ. 



263 



high degree of isolaterality shown in Fig. 17, G is due to the 

 fact, that this leaf had recently been cleared of snow, or to 

 some other cause, I cannot tell. The specimens from Ice- 

 land showed essentially the same structure as those from 

 Greenland. 



Fig. 18. Minuartia verna. 

 (From N.E. Greenland; 27. 6. 1908; A. Lundager.) 

 A, A small shoot with a hraneh. B and F, Transverse sections of leaf. 

 There is strong bast tissue on the dorsal side of the vascular bundles. 

 C, A glandular hair. D, Transverse section of leaf. The sheath of the 

 vascular bundle is of the same thickness all round; see E, in which 

 the bast tissue, sieve tissue and the tracheal tissue are shown. 67, Epi- 

 dermis with stoma. H, Epidermis of ventral surface. (E. W.) 



In the Minuartia verna figured in Fig. 18, D, decided 

 dorsiventrality also prevails, but here the palisade-tissue 

 is on the dorsal side — probably in harmony with the erect 

 position of the leaves (4). 



