397 



entirely absent from the lower surface, but occurred to the 

 number of about 100 per sq. mm. upon the upper surface. 

 Resvoll records concerning specimens from Jacobshavn in 

 Greenland that they have none upon the lower and 126 per 

 sq. mm. upon the upper surface; and in those from an un- 

 named locality in East Greenland, 27 upon the lower as against 

 235 upon each sq. mm. of the upper surface ; and in specimens 

 from Bosekob, 34 on the lower surface as against 63 per sq. 

 mm. of the upper surface. Two palisade-layers usually occur, 

 constituting about one-half of the mesophyll; the individual 

 cells are about twice as long as they are thick, are barrel- 

 shaped and somewhat irregular. There is a gradual transition 

 from the palisade-layers to the spongy parenchyma which con- 

 sists of slightly branching cells and has numerous intercellular 

 spaces (Fig. 40, A). The sub-epidermal layer which is placed 

 close to the epidermis has cells which often branch more 

 abundantly than those of the rest of the spongy parenchyma. 

 The bundles are not accompanied by stereom. 



The area with the water-pores is situated almost at the 

 margin. The structure of the epithema is as in B. lapponicus. 



The specimen from Thingvellier was somewhat more com- 

 pact in structure and had slightly longer palisade-cells than 

 the rest of the specimens investigated. 



The leaf-stalk was like that of R. lapponicus. 



Rauunciilus lapponicus L. 



Lit. Hooker, 1833, I, p. 16. Hartz, 1894, p. 36. Norman, 

 1895, p. 10. Børgesen, 1895, pp. 236, 37. Ekstam, 1897, 

 p. 145. Abromeit, 1899, p. 31. Ekstam, 1899, p. 22. Resvoll, 



1900, figs. 7, 15, 19, 21, 24, 29, 34. Andersson & Hesselman, 



1901, p. 47. 



Alcohol material from Spitzbergen (Rendalen in Sassenbay, 

 15. 7. 1882); Greenland (Kororsuak, 19. 6. 1879; Sarfanguak (Hol- 

 stenborg), 21.7.1884; Kappinilik, 5.9.1885; Christianshaab, 

 2.7. 1888). 



XXXVI. 26 



