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6 
7 
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ZI 
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BRITISH FERNS. 
Fronds (stiff) simply pinnate, with entire lobes, the fruiting 
linear, the barren lanceolate .. .. .. .. Blechnum. 
Fronds (delicate) much divided, with small, obovate or oblong 
toothed lobes. . 7 
Sori forming a line close to the margin of the frond. 
Allosorus. 
Sori oblong, scattered on the surface of the frond. 
Gymnogramma. 
Fructification concealed by, or intermixed with, chaffy scales or 
hairs .. . .. 9 
Fructification in lines along the margin of the fronds, the 
indusium a membrane attached to the margin .. .. .. io 
Fructification in circular, oblong, or linear sori, on the under 
surface, without chaffy scales .. .. ..II 
Fronds deeply pinnatifid, with entire segments. Sori linear, 
concealed by the scales . io. Ceterach 
Fronds twice-pinnate, with small segments. Sori circular, with 
chaffy hairs intermixed .. .. .. .. IS* Woodsia. 
Tall, erect, stiff fern, ternately divided, with pinnate branches 
and sessile lobes .. .. .. Pteris. 
Delicate fern, not a foot high, much divided, with broad wedge- 
shaped lobes on capillary stalks. Adiantum. 
Sori oblong or linear, covered (when young) with a membrane 
attached along the side . 12 
Sori circular, either without any indusium, or covered (when 
young) with a membrane attached by the centre or by a 
lateral point .. .. 13 
Frond entire. Indusium opening in a slit along the centre. 
SCOLOPENDRIUM. 
Frond pinnate or much divided. Indusium opening along the 
inner side . Asplenium. 
Fronds simply pinnate, with entire or toothed segments or 
pinnas. 14 
Fronds pinnate, with pinnatifid primary divisions or pinnas, or 
twice or thrice pinnate * .. 15 
all twice or thrice pinnate leaves or fronds, the primary divisions 
l side of the main stalk are called pinnas , the ultimate divisions 
g the name of segments. 
