168 BRITISH FERNS 

A : IN 
3 
р 
Zl 
Fig. 189. О. regalis cristata (pinna). 
A bulbiferous form was raised from this by Мг. 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 
Рогүрорү) 
(Plate XXIV) 
This Fern, as regards make of frond, may be roughly described 
as a slightly coarser and considerably larger edition of the Oak 





