MM 


1/2. ` % BRITISH FERNS 
PoLYPODIUM VULGARE (THE COMMON POLYPODY) 
(Plate ХХУ) 
P. vulgare, which is by far the most widely distributed species 
of this genus, differs very markedly from the other three. It has 
once-divided, tough fronds, consisting of a long stalk, continuing as 
a midrib bearing two rows of normally bluntly tipped side divisions, 

Fig. 194. 2. vulgare (pinna). 
as seen in Fig. 194, forming a sort of double comb with well- 
separated broad-based teeth, the frond tapering gradually to a 
blunt point, or perhaps with ршпа set on endwise, even the 
normals varying somewhat in different districts. Its native habitats 
are on the tops of old walls or roofs, where dense colonies some- 
times accumulate, along the hedges in the stony dykes which back 
them, in the forks of old trees, and even on the trunks, and in the 
woods on elevated masses of woodland debris and rocky detritus. 
Its fronds may attain a length of two feet under very favourable 
circumstances, .but ordinarily are less than half that size. The 
spores are borne in very conspicuous round masses on the frond 
backs, and are of a brilliant orange yellow, the spores themselves 
being of similar colour, a solitary exception in British species. 
Both capsules and spores are also comparatively large, the spore 
heaps, under a lens, resembling heaps of oranges. The rootstocks 
branch and spread on the surface, not burrowing, as in the other 
‚species of the same family ; they are also much thicker and fleshier, 
often às thick as one's little finger. The fronds spring from these 
singly, and do not form clumps. As their tree resorts indicate, 
leaf mould and good drainage are essentials to successful culture, 
апа shallow pans, providing room for the travelling rootstocks, are 
preferable to pots. This species is perfectly evergreen, the fronds 
lasting well into the second season, until new ones arise to replace 
them. The other members of the family will be treated of under 
their respective headings. This species has been very liberal in 
“ sports," many of which are of great beauty, as is seen by the 
nature prints in the Appendix. 





