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A TABLE OP THE GROUPS AND GENERA OP THE 
BRITISH FERNS AND ALLIED PLANTS. 
I. FERNS =FILICES. 
Flowerless plants, bearing seed-vessels ( spore-cases ) on 
their leaves {fronds), at the backs {dorsal) or margins 
{marginal). The British Fc-rns belong to groups which 
are called Polypodiacege, Osmundacege, and Ophioglos- 
sacese. 
POLYPODIACE/E = Ferns having the leaves rolled up 
in a circinate or crosier-like manner while young; and 
the spore-cases girt with an elastic ring, and bursting 
by an irregular transverse cleft. It comprises several 
lesser groups or sections, called Polypodiece, Gymno- 
grammew, Aspidieoe, Aspleniece, Blechnece, Pteridece, 
Adiantece, Woodsiece, and Hymenophyllece. 
§ POLYPODIES = Ferns whose round clusters of 
spore-cases have no special membranous cover {in- 
dusium). It contains the genera Polypodium and 
Allosorus. 
