226 THE BRITISH FERNS. 
occasionally somewhat crisped. This rare and very peculiar variety 
was found in 1854, by Dr. Kinahan, on the Sugar-loaf Mountains 
in Wicklow, Ireland. [Plate XCVI B.] 
25. dentigerum (M.). An elegant and constant form, of vigorous 
growth, the sterile fronds being eight inches to a foot long, and 
an inch and a half wide, gradually narrowed below, and forked 
at the tips; the segments are acute, and especially in the lower 
half of the fronds, much toothed in a very unequal manner, pro- 
ducing the appearance of being irregularly serrated. The fertile 
fronds are forked once or twice toward the tips, and the segments 
are occasionally forked. It was found in the neighbourhood of 
Windermere by Mr. F. Clowes. 
26. fissum (M.). The peculiarity of this vigorous form is, that 
the apex of the rachis is, as it were, split down a few inches, both 
sides of the resulting branches bearing lobes, but those on the inner 
sides are rudimentary, or very much smaller than those of the outer 
sides; the apices are occasionally somewhat multifid. The appear- 
ance produced by the inequality of development in the lobes of the 
branches, is similar to that of some kinds of Gleichenia. It has 
been found near Tunbridge Wells, and also near Todmorden; and 
is tolerably constant. 
27. bifidum (Woll.). In this which is a vigorous subpermanent 
form, not uncommon, the tips of the segments are more or less 
uniformly forked in a bifid or trifid manner, as in the var. bifidum of 
Polypodium vulgare. The apex of the frond is also sometimes multifid. 
The lobes, both of the fertile and barren fronds, are affected, but not 
uniformly. It has been gathered in—Durham : Blaydon Burn, 7. 
Wilcke. Yorkshire, A. Clapham. Kent: Tunbridge Wells, G. B. 
Wollaston. Devonshire: Barnstaple, C. Jackson. 
28. multifidum (Woll.). This variety differs from the normal form 
in being once or more divided at the apex, but neither uniformly nor 
symmetrieall. Such forms are of frequent occurrence, in damp 
shady places, and many of them are not constant under cultivation, 
so that they require proving. It has been found in— Kent: Tun- 
bridge Wells, G. B. Wollaston (2 forms); Chislehurst, G. D. W. 
Devonshire: Ilfracombe, J. Dodds ; Marwood, Rev. F. Mules. Somer- 
setshire: Nettlecombe, C. Ehvorthy. Lancashire: Peck Hill, R. 

