The second division Osmundaceæ comprises those Ferns which apparently have flowers; the flowers, however, being merely sori, with the leaves on which they grew shrivelled up round them. The most remarkable of these is the flowering Fern (_Osmunda regalis_); but others are--the Grape Fern or Moonwort (_Botrychium_), a species of which, a native of North America, is called there the Rattle-snake Fern; and the Adder's Tongue (_Ophiglossum_). The Tree Ferns of New Zealand are magnificent plants. The trunk or stipe rises to the height of forty or fifty feet without a branch, and then terminates in a head of noble fronds, which hang down on every side like a plume of feathers. The wood of these trees when cut across, instead of being in circles like the wood of Dicotyledonous trees, or full of pores like that of the Endogens, is marked with a number of zigzag lines, the traces of the stalks of old fronds which have grown together and formed the stipe.
ORDER CCXII.--LYCOPODINEÆ.--THE CLUB-MOSS TRIBE.
These plants appear to occupy the intermediate space between the Ferns and the Mosses. They have creeping stems, and grow two or three feet high; the erect stems being clothed with imbricated leaves, in the axils of which these are produced. Some of them open into three or four valves, and contain sporules; while others are only two-valved, and contain a kind of powder, which some suppose to be pollen, and others abortive sporules. In some of the species, the thecæ are produced in bracteated spikes, which resemble the young strobiles on a Spruce Fir. The seeds of the common Club-moss (_Lycopodium clavatum_) are used at the theatres to imitate lightning.
These are aquatic herbs, the thecæ or receptacles of which are always found in the axils of the leaves near the root. In the genus _Isoetes_ (Quillwort) these are of two kinds, like those of the Club-mosses, the one containing powder, and the other granules; but in Pepper-grass or Pillwort (_Pillularia_), the receptacles are four-celled, and each cell contains both powder and granules. _Marsilea_, from which the order takes its name, is a native of Italy and other parts of the south of Europe, where it grows in the same manner as Duckweed does with us.