CHAPTER II. Of Tribes.
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CHAPTER II.
OF TRIBES.
Ferns are divided into tribes principally by the microscopic characteristics of the position and form of the annulus, and the manner in which the capsules burst; we should, nevertheless, recommend any one wishing to find the name of a fern, to commence by trying to refer it to its proper tribe. This may often be done even without the aid of a microscope; thus the tribe Hymenophylleae may always be recognized by the translucent frond, only one of the tribe, amongst those found in New Zealand, failing in this characteristic, and that one having its sorus so evidently projecting beyond the margin of the frond as to leave no doubt to which of the tribes it should be referred. Then again the stalked spikes, (quite distinct from deformed fronds,) of the Ophioglosseae are plain enough, and the Cyatheae may also readily be distinguished, the globose sorus being quite apparent to the naked eye and with the help of a magnifying glass or pocket lens, the elevated receptacle may be plainly seen. Of the other tribes, a beginner, without microscopic aid would be very apt to confound the members; for instance he might not be able to decide whether a fern having naked sorus belongs to the first, the sixth or the fourth tribe. Still something is gained by the enquiry being narrowed to these three tribes; the genera comprehended in them must next be consulted, and here the more particular descriptions will most likely lead to a decision that it belongs to one of two or three genera, even if it cannot with certainty be referred to its own particular genus. Finally the species must be sought, and if due attention be paid to all the little peculiarities of the fern, one description only will be found to suit it exactly. Still it is not improbable that one beforehand totally unacquainted with botany may at first fail in naming a fern; we can only recommend such to persevere, presently they will come to one with more clear characteristics than the rest, they decide without a doubt its name, others that before seemed to tally with that description fall back into their own places and, finding here one and there one, order gradually arises out of confusion.
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Tribe I. Gleicheniaceae. Capsules in each sorus 1-6, without stalks, bursting longitudinally, completely surrounded by an oblique or transverse ring. Gen. I.
Tribe II. Cyatheae. Sorus globose, capsules with an incomplete vertical ring, placed on an elevated receptacle, often mixed with jointed hairs. This tribe includes all the tree-ferns of New Zealand. Gen. II-IV.
Tribe III. Hymenophylleae. Sorus at or beyond the margin of the frond, always terminating a vein; capsules on a thread, or club-shaped often much elongated receptacle, girt with an oblique ring. Fronds very delicate and translucent (except in Loxsoma.) Gen. V-VII.
Tribe IV. Polypodieae. Sorus generally on the back of the frond, rounded or linear; capsules not placed on an elevated receptacle, stalked, partly girt with a vertical ring, bursting transversely on the side where the ring is wanting. This large tribe may be divided into:
Sub-tribe A. Sorus covered with the more or less altered margin of the frond. Gen. VIII.-XIII.
Sub-tribe B. Sorus covered with involucra. Gen. XIV-XXI.
Sub-tribe C. Sorus naked. Gen. XXII.-XXX.
Tribe V. Schizaeeae. Sori arranged in overlapping spikes or on divisions of the frond bent back and altered; capsules not stalked, striped at the apex as they terminate in a horizontal ring. Gen. XXXI, XXXII.
Tribe VI. Osmundeae. Sori naked; capsules stalked, with a broad, dorsal, incomplete ring bursting lengthwise. Gen. XXXIII, XXXIV.
Tribe VII. Marattieae. Capsules without a ring, combined into an oblong or linear mass (sorus) which bursts down the middle. Gen. XXXV.
Tribe VIII. Ophioglosseae. Sori in stalked spikes, distinct from the frond, without a ring, globose, bursting transversely into two valves. Gen. XXXVI, XXXVII.
