In reverting to the various stages of development from the spore on the frond to the fully-grown plant, most persons have observed what they choose to call seeds on the underside of the frond (though not always necessarily on the underside). They are not, as we have just said, real seeds, but spores, the first process towards the development of a fresh plant. It may be mentioned briefly that about the year 1840 Professor Nageli, of Zurich, announced that he had made the discovery that in the Marchantia-like germinal frond (i.e., whilst in the Liverwort-like condition) were to be seen the organs of reproduction; and in about the year 1845 Count Suminski, of Berlin, confirmed the existence of these so-called Antheridia, and also that two kinds of cells existed on the young germ frond, and that the male cells on bursting threw out spiral thread-like bodies, thickened at one end, and furnished with cilia about the thickened part, and these, from their activity, were called "Animalcules." The Count farther stated that he had seen one of these spirals landed in a female cell. Hofmeister has since then distinctly observed the terminal end of the new axis produced within the pistillidium, (or female cell,) and looked upon the globular cellule in its centre as itself the radiment of the stem, the embryo originating from a free cell produced within it. Mettenius observed a nucleus within the globular cellule. Mereklin then declared that the spiral filaments swarmed about the postillidium in numbers, and that he had seen them on rare occasions penetrate it. Professor Henfrey, about 1850, wrote an interesting article on this subject.
Spores, when they are sown, germinate, yet they need not necessarily produce the same form as the frond from which they are taken. In their caterpillar or Marchantia-form stage of life they are said, as before mentioned, to flower, to have male and female organs or cells, (more male than female cells) and these be it remembered are before there are any fronds, and it seems probable that it really depends upon how this impregnation is effected as to what kind of frond springs up from the germinal frond. The female organs are described as cells, and the male organs as spiral filaments which are tossed into the air, some of which, by landing in these cups, fertilise the plant in its caterpillar stage, and thus enable it to put on its butterfly-life or fronds.
Let an example be taken in the Lady Fern, where a number of varieties have been sown together. Now, if a spinal filament from the variety Vietariæ be tossed into one of these female cells, we may naturally expect the fronds when they do appear to be more or less cruciform, like those of the variety Vietariæ; whilst if this filament had been thrown from the var. miltifidum instead, the result would be quite a different plant, a multifid but not a cruciform frond, unless the female cup belonged to a cruciform variety, under which circumstances there would probably result a combination of the two forms. Hence the endless variety that are now to be seen in a good collection. When once an abnormal form has been obtained, it seems only necessary to get a pedigree, i.e., three or four generations, and it becomes almost impossible to raise a seedling of the original normal form; whilst without this abnormal blood it is equally almost impossible to raise any but normal forms.
As regards the various normal forms that species will assume, it is a singular fact that most of our British ferns put on appearances closely in imitation of each other, that the varieties oi each species have many characters in common, and that a certain law of form of variety seems to extend more or less through both British and exotic species. The usual forms running through nearly all our British ferns are those having the fronds crested, crisp, imibricated, confluent, multifid, acuminate, narrow, plumose, interrupted, depauperate, vanmose, and dwarf; and not only this, but we have the multiple of these, or the com-
