37 2 
THE FERN WORLD 
towards its base. It is simply pinnate, the pinnae being 
generally set in pairs, but sometimes in alternation, along on 
opposite sides of the rachis. The shape of the little pinnae 
is roundish oblong, and their margins are finely notched or 
serrated, and usually attached to the rachis by a very short 
but distinct stem. The venation consists of mid-veins 
running through the pinnae with branching venules pro- 
ceeding to the marginal teeth. The sori, borne on these 
venules, are narrow and oblong, covered when young by 
indusia of the same shape, but being ultimately set free by the 
bursting and disappearance of the indusia, and then becom- 
ing confluent. It is to be noticed, that from the position of 
the sori on the venules in this Fern they appear when crowded 
to be clustered in the centre of the pinnae. This is one mark 
of distinction between Vi ride and Triehomanes, for in the case 
of the latter the fructification, when ripe, mostly completely 
covers the under sides of the pinnae. The rootstock of the 
present species is somewhat slender, but it is furnished with 
long, wiry rootlets. There are about twelve recorded 
varieties of Asplenium riride. 
Distribution. — On the continent of Europe this species 
is found in the following countries ; namely, Belgium, 
Bohemia, Croatia, Dalmatia, Finland, France, Germany, 
Greece, Italy, Lapland, Norway, Russia, Spain, Sweden, 
and Switzerland. In Asia it is found in India and Siberia. 
In America it is an inhabitant of the Rocky Mountains. 
It is also found in Peru. In England its habitats are 
Carr-edge, in the county of Chester ; Aslmess Gill, Borrow- 
dale, Borrow Force, and Gillsland, in Cumberland ; Buxton, 
Castleton, Cavedale, and Dovedale, in Derbyshire ; Falcon 
Clints, Teesdale, and Weardale, in Durham; Dulesgate and 
Staley, in Lancashire: Beacon Hill and Charley Forest, in 
Leicestershire; on the .banks of the river Irthing, in North- 
umberland; and at Dovedale, in Staffordshire. It has also 
