WILD FERNS 



229 



fresh and bright in June and stand far into the winter, 

 only perishing with severe frost. 



In some places Polypodies will grow on the trunks 

 and branches of rather stunted Oaks. In a wood 1 

 used to know in the Isle of Wight, where a thick 

 growth of small Oaks came down to within twenty 

 yards of high-water mark, this was the rule rather 

 than the exception ; but in my neighbourhood I have 

 only seen a single case of a wood where the Polypodies 

 grow on the Oaks, and that is only in one sheltered 

 corner at one edge of the wood. If it happens there, 

 I always wonder why it does not occur oftener. There 

 are plenty of stunted Oaks about, and plenty of Poly- 

 podies, why therefore does not the happy combination 

 oftener come about ? 



The fine Hart's-tongue Fern is rare about here ; it 

 wants a strong loamy soil. I remember a few plants 

 of it in the edge of one ditch, but that ditch has long 

 been buried under the raised approaches to a railway 

 bridge. It is fairly plentiful a few miles to the south 

 in the clay lands of the Weald. But I sometimes 

 see it a few courses down the mouth of a well, grow- 

 ing out of the relics of lime in the decaying joint, and 

 its occurrence in a curious way in a railway wall will 

 be described presently. 



The Ferns that seem to have least need of water, 

 after Polypody, which is frequent in old walls, are the 

 two other most common of wall Ferns, the Wall-Rue 

 (^Asplenium r^da-onuraria) and the Wall Spleenwort 



