FEEXT COMBES. 
79 
The other Folypodivms which, though found in 
the British Isles, are as yet unknown in Devon, 
are, first, P. alpestre, which so greatly resembles 
Athyrium Mlix-foemina as to have been for many 
years mistaken for it, being distinguished by the 
roimd masses of seed ; hitherto it is only known as 
growing in Scotland. Secondly, P. Robertianvm or 
calcareum^ which, as far as our experience goes, is 
not found in Devon ; it somewhat resembles P. 
Bryopteris, but is erect instead of drooping ; both 
stem and fronds of a pale green colour, mealy in 
appearance from minute glands with which the 
whole plant is covered, giving forth a pleasant 
scent when the hand is passed over the fronds. 
P. Bohertianim flourishes in limestone districts : 
Cheddar, in Somersetshire, is one of its habitats. 
PoLTSTiCHUM. — Masses of seed round ; indwsium 
round, attached hy its centre, 
PoLTSTiCHTJM ACTJLEATTJM. FricMy Shield Fern. 
Frond lance-shaped, twice divided ; pinnules 
joined to the midrib by their base, which is very 
much narrowed, slightly auricled, that is, enlarged 
on the side next their midrib ; whole plant rigid 
and prickly, dark green, two or three feet high ; 
frond narrowed at the base ; stem clothed with 
broad chafiy scales. 
