VI 
European Ferns. 
crozier-like body. In botanical language, the vernation or prefoliation is circulate, and this is 
very characteristic of ferns and very rare in other plants. One order of ferns, however, does not 
have this kind of vernation, the Ophioglossacea, containing the Adder’s-tongue and Moonwort, and 
from this and other special characters the group is often separated from the true ferns. Another 
peculiarity of the development of fronds is that the base is first 
formed and first unrolled, as any one can see in watching the 
expansion of a large fern, the lower portion being quite spread out, 
whilst the upper part is still in process of evolution. In some cases 
the growth of the top continues for a long time, as in the Climbing 
Fern ( Lygodium ) ; this kind of growth is called basifugal. 
We shall presently see that the fructification is produced on the 
fronds. Usually all the fronds produce fructification, to a greater 
or less extent, according to accidental circumstances ; but in a con- 
siderable number of ferns there are always some fertile and some 
barren fronds, bearing definite relations to one another, and very 
generally the two kinds of fronds differ considerably in form, size, 
and often in shape. Our Hard Fern ( Blechnum boreale ) and the 
Ostrich Fern ( Onoclea Struthiopteris ) are examples. This dimor- 
phism, as it is called, in the two kinds of fronds, may be carried to 
an extraordinary extent, as in the Elk’s-horn ( Platycerium alcicorne ), 
familiar in our greenhouses, where the barren fronds are flat, small, 
and undivided, and spread out over the surface on which the fern 
grows, while the fertile ones are erect, large, and branched like a 
stag’s antlers. Another very striking example is found in Tri- 
chomanes ( Hymenostachys ) e/egans, where the sterile fronds are 
numerous and deeply pinnatifid, much as in the common Polypody, 
whilst the fertile ones are only two or three in number, and simply 
linear with the numerous receptacles crowded along the edge. Or 
we may instance Polypodium ( Drynaria ) which well deserves its 
specific name (diversifolium) since the two kinds of fronds are so 
different that they would be supposed to belong to quite distinct plants ; the sterile ones are 
a few inches long, sessile, oblong-ovate, slightly lobed, and brown in colour like a dry oak-leaf ; 
the fertile are from two to four feet in length, on long stalks, with long distant, linear, bright 
green pinnae. We might give many other remarkable cases, but we must now pass on to 
consider the fructification itself. 
Fructification. — As above remarked, ferns have no flowers ; consequently, they have no seeds, 
for seeds can only be produced by flowers of some kind or another. The little bodies which 
reproduce — after some curious changes and developments, to be presently noticed — the Fern- 
plant are, as in the case of other Cryptogamic plants, called spores. They are excessively small, 
and contained in little capsules, called sporangia, of which we shall presently speak. These 
sporangia, or capsules, are variously arranged, but there are always several, often very many, 
together, and the group which they form is termed a sorus, the point at which they are attached 
being called the receptacle. The sori are the little patches, usually brown in colour, so noticeable 
on the under surface of fully-grown fronds, which distinguish them also so readily from true 
leaves. They vary very much in their position and arrangement, and upon these points the 
classification of ferns is very largely based. It will be found, on examination, that in most cases 
THE MOONWORT ( Botrychium 
Lunar id). 
