


136 THE BRITISH FERNS. 
observes :* * there is no doubt that the sori are really produced on 
the upper side, and that the frond is not reversed, like the leaves of 
Alstremeria or the lacinie of Schizea, as the structure of the sori- 
ferous side is essentially that of the upper and not of the under 
side.” We can only, from these’ instances, draw the inference that 
there exists in the vascular system of ferns, a proliferous power, 
which may be developed in any direction. 
The common native Scolopendriwm is one of the most remarkably 
prolific of varieties or variations, among known ferns; the greater 
part of these, though not unfrequently altogether monstrous in their 
development, retaining their peculiarities under cultivation. Several 
forms very distinct in themselves, and distinct also from the parent, 
have been produced from the spores under artificial treatment; and 
we cannot doubt from these instances that the same process is going 
on, more slowly indeed and less perceptibly but with equal certainty, 
in a state of nature, giving rise to new forms, a proportion of which 
endure on, and become perpetuated. 
The normal condition of the veins in Scolopendrium is to lie in 
parallel-forked lines, branching at the base but not uniting upwards. 
This normal arrangement is sometimes disturbed in varieties which 
assume a distinctly abnormal character, the tissues becoming irre- 
gularly contracted, and the order of the venation deranged, so that 
the venules here and there unite to form an irregular reticulation. 
Some forms become very much affectedin this way, their venules 
becoming generally reticulated. 
The name Scolopendrium has met with the general approval of 
pteridologists. Tt has been however latterly objected to by Mr. 
Newman, who proposes to substitute that of Phy yllitis, on the ground 
that the former name having been originally applied by Linnzeus as 
a specific appellation, it is not competent to be used as a generic 
title. We are unable to discover any force in this objection, which 
is, moreover, negatived by the practice of botanists. 
The pinnated species of Hart’s Tongue Fern are found in South 
Africa, the Philippine Islands, and the Islands of the Pacific Ocean ; 
and one or two simple fronded species, besides our native one, are 
- also found in extra-European habitats. 
* Berkeley, Introduction to Cryptogamic Botany, 509, note. 

