ON VARIATION GENERALLY. 
25 
forms, where the divisions end in a tail; and so on ad infini- 
tum. 
Proliferation characterises many varieties ; in this little 
plants appear on the stalks, edges, faces, or even the backs 
of the fronds. Many of the soft prickly Shield Ferns 
{Polystichum angulare) are thus affected, and look remarkably 
pretty when the young plants develop, as they do in pro- 
fusion all along the centre of the frond, and sometimes of 
the pinnse. 
The same form of variation, carried to excess, often so far 
obliterates the differences between the species that it re- 
quires an experienced eye to recognise them. Nothing, for 
instance, can be more dissimilar than the Lady Fern and | 
the Hartst ongu e ; yet there ^ a re f orm^ ^ of^ — dwarf and i 
extremely crested — that are as like as tw£ pea-s. The robust 
or giant forms of some of the smaller-growing species, and 
the dwarf forms of the larger, also contribute frequently to 
a likeness in the varieties which does not exist at all in the 
normal types. Fronds, for instance, of the common Poly- 
pody, fully 2ft. high, and beautifully cut, lose all likeness to 
the common, and resemble the Shield Fern varieties; while 
the dwarf form of Male Fern {Lastrea ;pseudo-mas ramosis si- 
mum), about Sin. high, would be relegated by most people 
to any species but the right one. — ^ 
The affinity, too, between the plain strap-shaped Ferns and | 
the much-divided ones is also curiously shown in several 
varieties of the Hartstongue {projectum series), in which 
there is a manifest and regular tendency all along the frond | 
to form pointed side divisions. The converse case is seen in 
some of the strap- shaped varieties of the Hard Fern, in which 
the double comb is almost obliterated. 
The great number of extraordinary forms of Ferns which 
have been found wild, owing to the careful examination to 
which the plants generally have been subjected by experi- 
enced Fern-hunters, leads, we think legitimately, to the 
assumption that the liability of plants to vary under culti- 
vation is not so much greater than it is generally assumed to 
be under natural conditions. The great bulk of the wild finds. 
