Caryophyllaceæ. 



249 



had, on the other hand, an elongated, richly-branching and 

 plagiotropic epicotyl-shoot." This was also the case with 

 the young plants reared by me under cultivation (Fig. 8). 

 The commonly occurring Arctic species Cerastium alpi- 

 num, which varies exceedingly in colour and hairiness, may 

 serve as a type. It may in certain conditions form very 



Fig. 9. Cerastium alpinum. 



A, From W. Greenland, '29th July, 1884. B, f. pulvinata. From 



E. Greenland, 25th Aug., 1900. (Hartz and Kruuse). 



dense cushions, with short flowering shoots; but long, erect 

 shoots, as much as 25 cm in length, may also be developed 

 from the mesocorm (Fig. 9). 



Cerastium nigrescens appears to behave like С alpinum. 

 It may be divergently branched, Avith long, erect shoots — 

 and this is the rule — or it may be densely branched, even 



