70 HISTORY OF BRITISH FERNS. 
fern ; while in others, they last hut from spring to autumn 
in each succeeding year. 
The Polypodies derive their common name from Poly¬ 
podium, which literally means, many-footed, and has been 
explained to apply to the branching of their creeping 
stems, the protuberances on which, in the earlier stages 
of development, have some supposed resemblance to the 
Polypes. 
Polypodium vuigare, Linnceus. 
The Common Polypody. (Plate I. fig. 2.) 
This is an evergreen Fern, growing abundantly on pol¬ 
lard trunks, mossy banks, moist rocks and walls, and old 
thatched roofs; and pretty generally distributed over the 
United Kingdom. When sheltered the fronds are of a 
cheerful but not bright green, and it may be then recog¬ 
nized by the comparatively large circular patches of golden 
orange or brown spore-cases ; indeed, it may generally be 
known by this feature alone, no other native sort having 
the fructification at all similar in appearance. 
This species has a creeping stem or rhizome as thick as 
one's finger, which is covered over with pale brown chaffy 
taper-pointed »cales. From its upper side spring the 
