154 



habit of the plant, the leaves do not require as mnch protection 

 as the species just referred to. Considering both the protection 

 indicated in the vegetative structure, and that which appears in 

 its anatomy, Diapensia lapponica occupies, however, a very 

 high position with regard to xerophytic adaptation, a position 

 which is not surprising when we recall the fact that this species 

 is a very old Arctic species, doubtless often a form adapted to 

 dry soil. The palisade-tissue should rather be characterized as 

 well-developed than as slightly developed, although the indi- 

 vidual palisade-cells do not attain any especially great height. 



7.— 12.-1908. 



