Caryophyllaceæ. 241 



consequently appears that the plant is on the point of transi- 

 tion to the semi-rosette stage. 



Silène maritima, which so far belongs to the Arctic flora 

 as it is found in Finmark and also in Iceland, appears to 

 have exactly the same morphology as S. venosa, viz. a numer- 

 ously branched mesocorm with erect long-shoots. 



If any of the other species should be placed together 

 with Silène acaulis, I believe it must be Arenaria ciliata. 



C. The Sagina nodosa type. 



To this group I refer Minuartia biflora, M. arctica, 

 M. hirta, M. groenlandica, M. macrocarpa, M. Rossii, M. 

 stricta, M. venia and the Sagina-species: S. cæspitosa, S. inter- 

 media, S. Linnæi, S. nodosa, S. procumbens, and, for in- 

 stance, the non-Arctic species, S. saxatilis and S. subulata. 

 Arctic species, which I have not been able to investigate 

 more closely, are Alsine arctica (Arctic America) and A. ma- 

 crocarpa. 



The above-mentioned species are generally low-growing 

 plants, with the basal portions of the shoots close-set, and 

 the flowering portions of the shoots protruding far outwards. 



Primary root. Here also the primary root is, almost 

 without exception (S. procumbens), the only root which is 

 of any importance; it holds together the erect branches of 

 the mesocorm. It remains during the whole life of the plant, 

 and may be long, although it is most frequently slender, 

 in accordance with the fact that the plants are small. 

 Although adventitious roots may perhaps occur in all the 

 species yet it appears that only in S. procumbens do they 

 promote layering. 



The characteristic feature in this group, when compared 

 with all the others, as far as I have been able to see distinctly 

 from the material to hand, is the fact that the primary 



