382 
THE FERN WORLD 
it, but sometimes in alternation — by short stems which are 
extensions of the mid- veins of the pinnae. Along the rachis 
on both sides is a very narrow leafy wing, and a similar leafy 
wing is observable along on each side of the short stems of 
the pinnae, the leafy expansion in this case running into or 
being gradually merged into the substance of the pinnae. 
Towards the apex of the fronds, the stalks of the pinnae 
become less and less distinct — the leafy wings, both along on 
each side of the rachis and along on each side of the points of 
attachment of the pinnae, becoming broader and broader — 
until finally the pinnae, meanwhile also becoming narrower 
and narrower, merge in the substance of the leafy wings, and 
the whole ends in a blunt-pointed lobe at the apex of the 
frond. The texture of the pinnae being thick and leathery, 
and somewhat opaque, the venation is not so easily seen as in 
most Ferns. It consists, however, of a mid-vein in each pinna. 
From this mid-vein there are venules on each side running 
obliquely towards the margin of the pinna and giving off 
veinlets once or twice branched. The sori are borne, on the 
under surfaces of the pinnae on each side of their mid veins 
in long oblique lines. They are very conspicuous, and are 
covered in their early stage bv conspicuous indusia of the 
same lineal form. But as the spores ripen, the indusia 
disappear, leaving the rich brown lines of fructification to 
contrast — as it beautifully does — with the dark shining green 
of the fronds. There are more than twenty variations from 
the normal form of Asplenium marinum. 
Distribution. — The range of this Fern will naturally be 
limited to the coast-lines of maritime countries. It occurs in 
Europe on the coasts of Corsica, France, the Ionian Isles, 
Italy, Portugal and Spain. Also on the north coast of Africa, 
and along the coasts of the Azores, the Canary Islands, 
Madeira, and St. Helena. It is found also on the coasts of 
North America, of the Bermudas, of New Brunswick, of Bio 
