CL A SS1FICA TION OF FERNS. 
II 
III. ASPIDIEiE. 
Sori covered with a circular or roundish indusium, 
springing from the back of the veins. 
4. Aspidium. —Sori dorsal, with circular, peltate, 
or reniform indusia. 
Nephrodium. —Sori round, with reniform indusium. 
IV. ASPLENIE^E. 
Sori covered with an oblong or elongated indusium 
which springs from the sides of the veins. 
5. ASPLENIUM. —Sori dorsal, with a straight and 
elongated indusium. 
6. SCOLOPENDRIUM. —Sori dorsal, elongate,, and 
placed together in parallel pairs, the indusium opening 
along the centre. 
7. Ceterach. —Sori dorsal, hidden amongst rust- 
coloured chaffy scales ; the indusium invisible. 
V. BLECHNEyE. 
The sori with an indusium forming longitudinal 
lines between the mid-rib and margins of the pinnas. 
8. Blechnum.—S ori dorsal, covered by a linear 
indusium. 
VI. PTERIDE^E. 
Bearing, on the margins of fronds, sori, which are 
covered with a special indusium. 
Pteris. —Sori in a continuous line at the edge of 
the frond. 
