This peculiar class includes many species of many different genera. While in some genera of this class only two or three species are represented, in others they predominate. The large genus asplenium is of the latter. This class is known from its curious way of multiplying or reproducing its species.
They are again divided into classes from the manner or disposition of the bulbils. Two of the best known ferns that are viviparous are Asplenium bul-biferum and Aspidium angnlare proliferum. We constantly see these in every place where ferns are grown. These have the bulbils or little plants scattered over the upper surface of the leaf, and are most readily increased by detaching the young plant and potting or laying the whole leaf on the surface of some pan of suitable soil where the young plants soon root and can be afterwards potted.
Another class has this proliferous character extending only to the stalk of the frond. Another class has but a single bulbil growing at the tip or end of the frond. And there is yet another which is classed as proliferous, but in a very different way from the other three. This includes the invaluable genus nephrolepis, and its proliferous character enables us to propagate it with such ease, and is also the cause of its being such a splendid basket fern. The nephrolepis have long, wiry stolons or underground rhizomes provided with latent buds which are constantly sending up fronds and forming young plants. As we all know, to sever this wiry rhizome or stolon from the parent plant is not felt by either, so our stock of the Boston fern and other nephrolepis is most rapidly increased by planting out medium sized plants in four or five inches of soil during summer. Besides those mentioned there are a number of viviparous or proliferous ferns, many of them highly interesting and handsome, but not desirable to the plant grower. These are adiantum, gymno-gramme, marattia, nephrodium, platy-cerium, polypodium, pteris, scolopen-drium, woodwardia and others; all have several representatives in this curious hen-and-chickens-like class.