252 Eu i;. Warmim;. 



large tufts." But these forms are hardly typically pulvinate 

 in habit. 



Adventitious roots may be found in the interior of dense 

 mesocorms. 



Winter-stage. Cerastium alpinum appears to be parti- 

 cularly evergreen. Helgi Jonsson examined it in East 

 Iceland on January 2nd; he mentions the dense hairy-cover- 

 ing of the protecting leaves (see Fig. 10). The living leaves 

 contained starch. He found living leaves also on C. caespi- 

 tosum, as Sylvén did in Central Sweden. Likewise, there 

 evidently occur living leaves on C. alpinum, according to 

 material preserved in alcohol, both at Upernivik on the 

 west coast of Greenland (G. Ryder) and in N.E. Greenland 

 (Lundager). But I found no starch in them. Lundager and 

 Ostenfeld (1917, p. 20) write about C. alpinum in N.E. 

 Greenland: "When the flowering plant, in the autumn, is 

 suddenly covered with snow, which remains during the 

 winter, all the parts of it are so well preserved, that in the 

 spring, when the snow has melted, they appear again and 

 apparently are as fresh as if they had quite recently un- 

 folded themselves." 



The older branches, as in the other types, are apparently 

 dead, because their bark is grey and wrinkled. This is most 

 distinctly seen in the prostrate branches; but in the spring, 

 fresh leaves develop from their terminal and lateral buds. 

 It is true that the bark-layer is dead, but on loosening it, 

 a fresh, green axis is found under it. In Denmark the same 

 thing happens in nature. I have described and figured the 

 wrinkled, older, subterranean runners which are also found 

 in Honckenya. Perhaps this phenomenon should be regarded 

 as a means of protecting the stem against transpiration 

 due to cold winds. 



