Caryophyllaceæ. 257 



root and lie prostrate along the ground, and are of a length 

 of about 25 cm or perhaps even more; some are subterranean. 



These hibernacula are described by Norman (1893) in his 

 "Flora Arctica", p. 26 (Christiania Videnskabsselskab), and 

 are figured by 0. Nordstedt in 1909 (Bot. Notiser, p. 51). 



The germination is described by Sylvén (p. 298). 

 A seedling develops in the first year a plagiotropic, very 

 richly branched aerial-shoot-system, of which some of the 

 shoots often become subterranean by being covered with 

 sand. 



Stellaria humijusa should perhaps be most properly 

 placed by the side of Cerastium trigynum. From the base 

 of the primary stem proceed, as in Cerastium trigynum, 

 numerous prostrate, richly branching and rooting, entangled 

 branches. On these are found small, thick-leaved shoots, 

 with short internodes, which are no doubt winter-shoots, 

 and when the buds open in spring, they do not seem to 

 elongate. In specimens collected on July 27th, far north- 

 wards (Upernivik), some of these shoots had unfolded and 

 flowered, while others had not (see Fig. 13). 



This species has a distinct, fairly long, but slender pri- 

 mary root. In addition to the creeping aerial shoots, sub- 

 terranean shoots may occur. 



With the exception of the above-mentioned short shoots, 

 it is hardly to be called evergreen. 



The shoots flower after a vegetative stage varying from 

 two to several years. 



G. The Stellaria media type. 



The last growth-form is represented by the present 

 species, which is widely distributed, but cannot be included 

 among the truly Arctic species. It has, however, been found 

 in several places in Greenland, north of the Arctic Circle, 



