50 
HISTORY OF BRITISH FERNS. 
6. Athyrium = Dorsal-fruited Ferns, having oblong reni- 
form indusia, attached by their concave side, the 
detached side fringed with hair-like segments. 
7. Asplenium = Dorsal-fruited Ferns, having the indusia 
straight and elongate, and attached by the side to¬ 
wards the margin of the pinnae or pinnules. 
8. Scolopendrium — Dorsal-fruited Ferns, having the sori 
elongate, and proximate in parallel pairs, the indusia 
opening along the centre of the twin sori. 
9. Ceterach = Dorsal-fruited Ferns, having the indusia 
obsolete, and the sori hidden among densely imbri¬ 
cated, rust-coloured, chaffy scales. 
§ LOMABIEiE = Ferns whose sori have special in¬ 
dusia, forming longitudinal lines between the midrib 
and margins of the leaflets or divisions of the frond. 
It contains the genus Blechnum. 
10. Blechnum = Dorsal-fruited Ferns, having the spore- 
cases in a continuous line between the midrib and 
margin of the divisions of the frond, covered by 
linear indusia. 
§ PTERIDEJE == Ferns the margin of whose fronds is 
soniferous, and continuously or interruptedly changed 
