168 



BRITISH FERNS 



Fig. 189. 0. regalis cristata (pinna). 



A bulbiferous form was raised from this by Mr. Clift, of Birming- 

 ham, bulbils being borne near the frond bases. 



Rotundata. — A round pinnuled form found in Ireland by Mr. 

 M. H. Phillips. 



Decomposita. — Found in Ireland by Mr. Alex. Cowan ; fronds 

 much more divided, and with saw-toothed pinnules, the fructifica- 

 tion taking the form of detached bead-like masses instead of slightly 

 crenate spikelets. 



THE POLYPODIES 



The Polypodium genus is represented in Great Britain by four 

 species, viz. Polypodium vulgare, the Common Polypody, P. 

 dryopteris, the Oak Fern, P. phegopteris, the Beech Fern, and 

 P- calcareum {Robertianum) , the Limestone Polypody. The name 

 Polypodium signifies many-footed, the rootstocks travelling on 

 or near the surface of the soil, and, as in the well-known Haresfoot 

 Fern (Davallia), the growing tips resemble more or less hairy paws. 

 In point of fact, however, many species, the Davallias themselves 

 to wit, do the same thing, but belong to quite different genera, the 

 actual generic distinction of the Polypodium family being a fruc- 

 tification, consisting of round or oval masses of spore capsules, 

 quite destitute of any protecting cover, so that the generic name 

 is another of those misleading ones which we have inherited from 

 the old times when botanical knowledge was very imperfect. 



Polypodium Calcareum' (Robertianum) (The Limestone 



Polypody) 



(Plate XXIV) 



This Fern, as regards make of frond, may be roughly described 

 as a slightly coarser and considerably larger edition of the Oak 



