66 
THE BOOK OF 
THE POLYPODIES. 
The Common Polypody (Polypodium vulgare). 
POLYPODIUM vulgare is one of a big family, whose spore 
heaps are round, or nearly so, and quite destitute of a cover 
or indusium. The generic name implies, however, “ many 
footed," and therefore refers to another feature altogether, viz., 
the creeping root-stock, which, however, is found in many 
genera of entirely distinct character, and therefore by itself 
gives no clue to species. In Great Britain we have four 
members of the family, viz., P. vulgare (the common Polypody), 
P. dryopteris (the Oak Fern), P. phegopteris (the Beech Fern), 
and P. calca- 
reum (the 
Limestone 
Polypody). P. 
alpestre, so- 
called because 
its spores have 
no indusium, 
no fernist can 
accept as 
other than an 
A t h y r i u m , 
especially as 
n many 
Athvria the 
indusium be- 
comes almost 
or quite a 
nullity. 
Among these 
species P . 
vulgare stands 
ab s ol ute ly 
distinct ; its 
creeping root- 
stock is thick 
and fleshy ; its 
fronds, simply 
p. vulgare plumosum Hadwinu. pinnate, are 
