208 Fr. J. Mathiesen. 



more evenly distributed as compared with the densely leaved 

 rosettes, where they are especially numerous towards the 

 apex of the leaf. The total number of stomates per leaf 

 seems generally greater on plants from Central Europe, than 

 on those from the Arctic Zone. 



In fig. 22, G, a transverse section of the leaf is given. 

 The outer walls of the epidermis are only slightly thickened, 

 and the stomates are either level with the surface of the 

 leaf, or slightly raised above this. The illustration shows 

 only one layer of palisades, but 2 and even 3 layers may 

 occur (see Th. Holm, Tab. VIII, fig. 4). The aèrenchyma is 

 exceedingly lacunar in structure, and its cells are strongly 

 branched. 



Dodecatheon frigidum Cham, et Schlecht. 



Lit.: Kjellman, 1883, p. 517. Eastwood, 1902, p. 211. Pax 

 and Knuth, 1905, p. 239. Ostenfeld, 1910, p. 62. 



Herbarium material from Arctic America (Port Clarence, 22nd and 

 26th July 1879, Fr. R. Kjellman; Herschell Island 18 / 8 1906, A. H. 

 Lindström). 



The geographical area of Dodecatheon frigidum seems to 

 be fairly limited. With the exception of a couple of 

 records in Oregon and Utah, which Pax and Knuth con- 

 sider to be doubtful, it has only been found on the shores 

 of Berings Straits and Alaska, and on adjacent islands. 

 According to Kjellman, it grows chiefly amongst shrubs 

 on mountain-slopes, but it may also be found on damp 

 plains near the beach. The shoot-structure resembles that 

 of the Primula species already described. The peduncle is 

 terminal, and the bud, which is to continue the growth of 

 the rhizome, developes in the axil of the uppermost foliage- 

 leaf. In the material examined by me, were some specimens 

 with an upward branching rhizome, which showed that the 

 buds formed in the axils of the lower foliage-leaves may 

 also attain to full development under favourable conditions. 



