OAK FERN. 
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OAK FERN, [one third the natural size). 
Polypodium Dryopterts, Linneus. 
The Oak Fern is one of our most elegant and delicate spe- 
cies : like the last, it is almost entirely confined to wild and 
mountainous districts, wet woods, and the vicinity of waterfalls. 
On the most bleak and exposed mountains it ascends to a con- 
siderable height, sheltering beneath ledges of rock, and under 
masses of stone. It principally occurs in our northern English, 
our Welch and our Scotch counties, but in Ireland is a fern of 
excessive rarity. 
The range of this fern, as regards England and Wales, some- 
what corresponds with that of Polypodium Phegopteris, but 
appears to be more restricted ; for so great a doubt attends the 
recorded locality in Devonshire, that it must be omitted until 
confirmed by fresh observation. If the island were divided by 
an oblique but irregular line, composed of the rivers Trent and 
Severn, and the Bristol channel, we shall find P. Dryopteris 
present in most of the counties to the north-west of this line, 
and nearly absent from those to the south-east ; this is the more 
