168 HISTORY OF BRITISH FERNS. 



Genus X. SCOLOPENDRIUM, Smith. 



THIS genus is botanically very distinct from all our other 

 native .Ferns ; and from other points of view is exceedingly 

 interesting. There is only one British species, but of this 

 there are several varieties, which have a perfectly distinct 

 aspect, owing to peculiarities in their development. They 

 are all evergreen, and on this account, as well as by reason 

 of their ornamental appearance and hardiness, they are 

 among the best of all Perns for out-door rock-work. The 

 genus is known from all others by the peculiarities of its 

 sori, which, though forming parallel oblique lines at intervals 

 on each side the midvein, and having the appearance of 

 being single if seen when mature, are in reality composed 

 of two sori, set face to face, and so close together as to be- 

 come laterally confluent. This is best seen just at the stage 

 when the indusia are bursting ; indeed, at a later stage of 

 development an unpractised eye would probably fail to ob- 

 serve any evidence that such was really the structure. 

 Nevertheless it is so; and the fructification, technically 

 speaking, consists of sori confluent in pairs, the two sori 

 forming each pair being placed face to face. 



Scolopendrium is merely an alteration of Scolopendra, the 



