156 
HISTORY OF BRITISH FERNS. 
a centipede and the lines of fructification produced on the 
fronds of the Fern. 
Scolopendrium vulgare, Symons, 
The Common Hartstongue, (Plate XV. fig. 1.) 
This is a common plant ; nevertheless its shining bright 
green^ though simple fronds, contrasting so beautifully 
with the feathery aspect much more common among the 
Ferns, secures for it admirers, whether seen in a wild or 
cultivated state. It grows in tufts. 
The fronds, which are evergreen, vary in length from 
six inches to a foot and a half, and even more, and are 
either stiff and erectish when growing under circumstances 
which render them dwarf, or more or less spreading and 
drooping when in situations which are favourable to 
enlarged development : in the former case the fronds are 
thicker and more leathery in texture ; in the latter, thinner 
and less rigid, from being produced in very damp shady 
situations. The usual form of the fronds is what is called 
strap-shaped, that is, narrow oblong-lanceolate, much 
elongated ; they taper towards, and are acute at, the apex, 
narrowing a little downwards, and becoming cordate at 
the base ; the margin is entire, or very slightly wavy, and 
