346 Morten P. Porsild. 



5) Iris sibirica L. (and relatecl species?) extend to the 

 coast on both sides of Bering's strait. 



As to the structure and biology of the majority of the 

 above-mentioned species the reader is referred to Kirchner, 

 LoEW & Schroeter's: "Lebensgeschichte" where — on 

 Alpine material — these questions have recently been treated. 



Widely distribut ed in the arctic territory are only 

 the two following species of the genus 



Tofleldia: 



1) T. pahistris Huds., circumpolar, common from the 

 subarctic territory far into the arctic, probably ^^ithout 

 reaching the purely high-arctic regions, however. 



2) T. coccinea Rich., N. Asiatic, N. American, found 

 besides in the northernmost two-thirds of Greenland, every- 

 where rare or perhaps overlooked; numerous of its Asiatic 

 occurrences are only known from previous erroneous deter- 

 minations, corrected by Ostenfeld (FL Arctica p. 32). 



A third species: T. calyculata Wahlenb. is distributed 

 throughout nearly all the mountain regions of Central Europe, 

 whence it often descends into the lowland, whilst it only in 

 a few piaces crosses the Alpine limit of forest: the variety 

 glacialis Reichenb. 



The structure and biology of T. calyculata is extremely 

 well-known, and the same applies partly to T. pahistris. An 

 account of this, based upon Alpine material, is found in 

 LoEw & Kirchner's: "Lebensgeschichte" p. 229 ff., a copious 

 literature being quoted here, too. Gp. also the description of 

 the closely related Narthecium ossijragum Huds. ibid. p. 244 

 fT., and Raunkiær p. 138 f[\ The following observations, 



