I923] Fernald, — Empetrum nigrum, f. purpureum 83 



in Dumortier's plant, the specific name flaccid 'a would become avail- 

 able; otherwise some other choice would have to be made. 



According to our present knowledge the true B. tricrenata is largely 

 restricted in eastern North America to the higher mountains of 

 Quebec and New England. It is usually replaced at lower altitudes 

 by a species in which the caducous habit of the leaves is even better 

 marked than in the European " Pleuroschisma tricrenatum var. 

 implexum." An account of this species follows. 



(To be continued.) 



