Nee 2 ae 
- CRYPTOGAMIA. FILICES. Polypodium. 
attly owing to the —— of a general resemblance in habit, 
partly to the different appearances observable in them at different 
ages, and partly to ddbacicas in the specific characters. Nor 
have authors always been scrupulously — in the applica. 
tion of the terms used in describing the leave 
he plants should not be gathered for ecstatic until of 
sufficient age to attain a full state of fructification, The terms 
employed in the subdivisions of the species, and in characterizing 
the individuals, should be precisely understood. ‘The attention 
should be more particularly directed to the lower parts of the 
leaves, wings, &c. for there it is that the characters are most 
constant, and most observable, the extreme parts generally run~ 
ning together so as to baflle every attempt at description. 
The following tabular view of the different British species is 
offered as a means of facilitating their investigation ; the student, 
therefore, is advised first to compare the plant in question with 
hese characters, and then to look forward for the characters and 
descriptions given more at large. 
(1) Leaves wing-cleft. 
‘P. vulga’re. Lobes oblong, somewhat serrated, blunt. 
(2) Leaves winged. 
P, tnad tis. Wings crescent-shaped ; Seely and sharply 
rated : stems with chaff-like scales 
r Tver! se. Wings opposite, cng at, bhint, hairy un- 
_ derneath, very entire at the bas 
P. arvo’nicum. Wings pear-shaped wing-cleft, hairy 
underneath : stems 
P, Phegop’teris. Wings eeu wing-cleft, 
— at the base; hairy underneath. 
P, Oreop’teris. Wi trap-spear-shaped, wing-cleft : 
he bluntish : vsahuntets oe capsules at the edges. 
(3) Leaves winged ; wings deeply wing-cleft. 
P. F. mas. Wings strap- Yip aoa ; lobes blunt, finely” 
cha 
et: stem 
P, Thelyp’teris. Wings spear-thapet: acute ; lobes very 
entire 
P, denta’tum. Wings egg-spear-shaped, opposite ; lobes 
egg-shaped, vent sparingly cut at the sides, finely 
toothed at the : 
D 
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