275 



some are placed in rows which are decidedly oblique to the 

 long axis of the leaf (Fig. 21 Z), E). 



The cells of the spongy parenchyma are rounded, un- 

 branched, and most compact immediately beneath the lower 

 epidermis (Fig. 21, C). 



The veins are without stereom and have hyaline bundle- 

 sheaths (Fig. 21 D). 



Fig. 22. Saxifraga tricuspidata. 



The epidermis of the leaf: A and B, Upper surface. C and D, Lower surface. 



(A, B, C, D -^ii). 



The hydathode opens upon the upper side of the leaf- 

 margin (Fig. 21); it does not secrete lime, in one solitary 

 specimen the water-pores were gathered very closely together, 

 six being directly in contact with each other. 



I have investigated specimens of this species from Disco 

 (July 20, 1884), Amerdlok (July 11, 1884), Upernivik (May 10, 

 1887). Thev were all alike. 



