426 THE ALPINE FLORA 



native of woods and rocky debris in all Swiss mountains, 

 especially in the calcareous ones ; P. Dryopteris, the Oak- 

 fern, which differs by a more slender and more rampant 

 rhizome, by shorter, blunter, glabrous fronds, whose 

 segments are always opposite ; a native of woods in the 

 alpine and sub-alpine zones ; lastly P. Phegopteris or 

 Beech-fern with toothed and hairy leaflets, the lowest 

 pair bent backward. The main outline is an elongated 

 triangle. It differs also from the two above in that the 

 frond is pinnately divided and not in the least ternate. 

 From cool places in the granitic Alps and odd woods in 

 the Jura. 



