CHAPTER III. Of Genera.
[Image of page 8]
CHAPTER III.
OF GENERA.
As we descend from the great divisions of our subject to the less, we find much more obvious characteristics by which to guide our enquiries. Instead of having, as in the last chapter, to turn our attention to the capsules and their annulus we find that the generical description is chiefly concerning the shape and position of the sorus, the absence or presence and form of the involucre and the manner in which the veins are arranged, for although other characteristics maybe occasionally mentioned, those of fructification and venation are the most important.
TRIBE I. --GLEICHENEACEAE.
Gen. I. --Gleichenia. Sorus naked, although in some of the species the margin is so curled back as almost to conceal it. The ferns of this genus are stiff and leathery in texture; stipes erect, stiff, generally very tall and slender; the frond branches dichotomously, --that is, divides at one point into two which branches in their turn divide in like manner, often bending gracefully on either side. 4 Species. This genus is divided into two sections:
S 1. --Eugleichenia. Sorus at the point of a veinlet. Segments of the pinnae very narrow and notched. Sp. 1, 2.
S 2. --Mertensia. Sorus at the middle or angle of a veinlet. Segments of the pinnae with even edges. Sp. 3, 4.
TRIBE II. --CYATHEAE.
Gen. II. --Cyathea. Sorus on the back of the frond, removed from the margin, although when very ripe the whole of the back of the frond is sometimes covered by the mass of fructification. Involucre globose, at first closed but when ripe bursting irregularly
[Image of page 9]
TRIBE II-III. GEN. Ill-VI.
either at the base or apex and forming a kind of cup whence this genus takes its name. A large genus of tree-ferns. 4 Species.
Gen. III. Alsophila. Sorus on the back of the frond; receptacle prominent; no involucre; trunk generally arborescent, but in the New Zealand species often absent. 1 Species.
Gen. IV. Dicksonia. Sorus near the edge of the frond; globose, on an elevated receptacle, involucre two-valved, the "true" one springing from the point of a vein and often very inconspicuous, the "false" one formed of a lobe of the pinnule turned back and covering the other. Having generally an arborescent stem. 3 Species.
TRIBE III. --HYMENOPHYLLEAE.
Gen. V. Hymenophyllum. Sorus marginal; the receptacle on which the capsules are arranged is either immersed in the edge of the frond or protruded beyond it. The cup-shaped or boxlike, often flattened, involucre is formed of the substance of the frond, the outer edges of the valves do not unite; the involucre is sometimes produced beyond the edge of the frond and stalked. These ferns are almost always to be found in damp forests and are easily recognized by their delicate, pellucid, bright green fronds in which only two genera at all resemble them. 15 Species, which may be divided into:
S A. Fronds quite smooth; margins toothed like a saw but without hairs. Species 1-5.
S B. Fronds smooth or with the costa and rachis only hairy; margins not toothed. Species 6-13.
*a. Fronds pinnatifid, rarely pinnate below; the rachis, and generally the stipes having a margin of the texture of the frond. Species 6-10.
*b. Frond pinnate below, stipes and lower part of rachis without the fine margin. Species 11-13.
S C. Costa, margins and sometimes the surface of the frond clothed with hairs, which, when closely observed, may be seen to radiate in little bunches from various points. Species 14, 15.
Gen. VI. Trichomanes. Sorus marginal; involucre tubular, of the same texture as the frond, narrowed at the base, widening at the apex; the receptacle often protruding like a hair. This is a more tropical genus than Hymenopyllum from which it may be distinguished by the tubular or trumpet-shaped involucre which is less obviously two-lipped, often quite circular at the mouth, and
[Image of page 10]
TRIBE II-IV. GEN. VII-XII.
also by the protruding thread like-receptacle. Fronds generally delicate and pellucid. 6 Species.
Gen. VII. Loxsoma. Sorus marginal, situated in the angles of the notched pinnae; involucre thick in texture as is the frond; receptacle protruded; capsules crowded upon it and mixed with jointed hairs. 1 Species.
TRIBE IV. --POLYPODIEAE.
SUB-TRIBE A.
Gen. VIII. Adiantum. Sorus marginal, dotlike; involucre membranous, kidneyshaped, formed of the edge of the frond turned back and bearing the capsules on its under surface, its surface is veined, the veins being continuous with those of the pinnules. 6 Species.
Gen. IX. Hypolepis. Sorus dot-like, marginal, separate; involucre springing at its point from a vein formed of a recurved lobe, but sometimes the margin is so slightly bent back that the sorus is really naked. In habit and general appearance this genus differs widely from the preceding one, which may always be recognized by its marginal, kidney-shaped, involucres. 3 Species.
Gen. X. Cheilanthes. Sorus marginal; the capsules very numerous and prominent, often covering the small pinnules; involucre as in Hypolepis, except that, instead of isolated teeth or lobes of the pinnules, larger portions of the margin are bent back over the sori, forming, in a greater or less degree, a continuous involucre. The only New Zealand representative of this genus is much smaller and more insignificant than those of Hypolepis, as will be seen on reference to the species. 1 Species.
Gen. XI. Pellea. Sorus line-like or oblong, marginal, growing towards the end of the simple or forked veins, at length forming one mass, a continued, more or less broad, marginal line of fructification; involucre narrow, continuous, formed of the membranous edge of the frond at first turned back and at length frequently spread open so as to expose the entire fructification. Both the New Zealand species are pinnate. This genus is included in Pteris by Dr. Hooker, but in a more recent work by Sir William J. Hooker it has been separated on account of the difference in the position of the capsules. 2 Species.
Gen. XII. Pteris. Sorus line-like, marginal, continuous, capsules inserted in the groove between the frond and the involucre; the latter marginal, continuous, having a dry shrivelled appearance. 6 Species, which may be divided into:
[Image of page 11]
TRIBE IV. GEN. XIII-XVII.
S. Eupteris. Veins forked, free. Species 1-3.
S. Litobrochia. Veins more or less anastomosing. Species 4-0.
Gen. XIII. Lomaria. Sori on a separate frond, capsules finally covering the whole surface of the narrow pinna; involucre marginal, continuous, thin and shrivelled; sometimes reaching to the costa, but when the fructification is ripe often very inconspicuous. The fronds generally growing in tufts, the central ones bearing fructification, the rest barren. 13 Species, which may be thus divided:
S A. Sterile fronds, pinnate, having their pinnae stalked. Species 1-3.
S B. Pinna of barren fronds not stalked but joined by a more or less broad base to the rachis. Species 4-12.
S C. Frond bi-pinnatifid. Species 13.
SUB-TRIBE B.
Gen. XIV. Davallia. Sorus marginal, oval or circular; involucre rising from the point of a vein, joined to the back of the frond by its base or by its base and sides. 1 Species.
Gen. XV. Cystopteris. Sorus on the back of the frond in the middle of a veinlet; involucre nearly circular but attached by a broad base to the sorus; veins forked and free. 1 Species.
Gen. XVI. Lindsea. Sorus linear, on or just within the margin, tipping with a line of fructification each of the little pinnules; involucre opening outwards, formed of two plates, the upper one of the same texture as the frond and formed of it, the lower membranous and rising from the ends of the veins. 2 Species.
Gen. XVII. Asplenium. This genus is distinguished by bearing on the back of the frond linear sori, covered by a linear involucre which is attached lengthwise to a veinlet, opening lengthwise and inwards; sometimes the fronds are cut or divided between every veinlet, when the sori become marginal and the involucres appear to open outwards, but if the whole pinnae be carefully regarded, it will be seen that the involucre really opens towards its costa. 9 Species which may be divided into:
S A. Fronds simply pinnate, pinnae toothed. In one species the lower pinnae are sometimes pinnate. Species 1-4.
S B. Fronds bi-pinnatifid, bi-tri-pinnate, sometimes divided into many long narrow pinnules, when the sori become marginal. Species 5-8.
[Image of page 12]
TRIBE IV. GEN. XVIII-XXVII.
S. Allantodia. Involucre membranous, arched, both margins attached to the vein. Species 9.
Gen. XVIII. Doodia. Sori short, linear or crescent-shaped on the back of the frond and forming a row on each side of the costa and parallel to it. Involucre linear, opening towards the costa and parallel to it, placed on an arching veinlet that joins two veins. 1 Species.
Gen. XIX. Polystichum. Sori placed on the middle of the veins at the back of the frond. Involucre circular, attached by its centre to the sorus, its edges free all round. 4 Species.
Gen. XX. Nephrodium. Distinguished from Polystichum by its involucre being kidney-shaped and attached by the sinus. 5 Species.
Gen. XXI. Nephrolepis. Veins forked, very close, sunk in the frond, terminating at some distance from the margin, a large joint, twice forked, the upper and shorter joint terminating in a sorus. Involucre kidney-shaped. 1 Species.
SUB-TRIBE C.
Gen. XXII. Goniopteris. Sori round, naked and numerous, placed on the middle of each veinlet; veinlets in each lobe free, but those nearest the costa meet those of the next lobe at an angle, 1 Species.
Gen. XXIII. Polypodium. Sori round, naked, placed on the middle of a veinlet; veins forked and free, never uniting again as in Goniopteris. 3 Species.
Gen. XXIV. Phymatodes. Distinguished by the large, naked sori, partly sunk in the frond, and the anastomosing veins. 2 Species.
Gen. XXV. Dictymia. May be recognized by the simple frond which is so thick as to conceal the veins, and by the large, naked sori which are often oval rather than round. 1 Species.
Gen. XXVI. Arthropteris. Veins forked, free; veinlets terminating within the margin; small, circular, naked sori at the end of the veinlet, forming a single series all round the pinnae, nearer the margin than the costa. 1 Species.
Gen. XXVII. Niphobolus. May at once be known by the thick white scales, covering its under surface and giving it an almost
[Image of page 13]
TRIBE IV-VII. GEN. XXVIII-XXXV.
woolly appearance. Frond simple, leathery. Sori numerous, round, protruding through the white covering. 1 Species.
Gen. XXVIII. Grammitis. Sori oblong or linear, naked, in one series on each side of the costa to which they are oblique; veins immersed in the simple frond. 1 Species.
Gen. XXIX. Gymnogramma. Sori naked occupying the veins and veinlets, hence often running in lines and forking, or covering the spaces between the veins and forming a mass of fructification. 2 Species.
Gen. XXX. Notholana. The only New Zealand species very much resembles Cheilanthes ternuifolia, but may be distinguished by its scaly, hairy frond; sorus marginal, naked, but sometimes partially concealed by the margin of the frond. 1 Species.
TRIBE V. --SCHIZAEAE.
Gen. XXXI. Lygodium. A remarkable genus of creeping, wiry ferns; fertile and barren fronds differing in form; fertile fronds repeatedly branching dichotomously, the stalk thus dividing three or four times between its point of junction with the stem and its fertile lobes, the leafy part of which is very inconspicuous, being almost concealed by the numerous little spikes of fructification with which they terminate. 1 Species.
Gen. XXXII. Schizaea. A very curious genus to be distinguished by the small pinnatifid limb or comb with which each frond or each pinnae terminates, and on which the capsules are arranged in two series, partially covered by its incurved margin. Ferns of this genus often have the appearance of withered stalks, with a little brown comb of fructification at the top. 3 Species.
TRIBE VI. --OSMUNDEAE.
Gen. XXXIII. Leptopteris. The New Zealand ferns of this genus are very finely cut, bright green and translucent. Capsules scattered over the back of the frond on the veins. 2 Species.
Gen. XXXIV. Todea. May be distinguished from Leptopteris by its fronds being very thick in texture. 1 Species.
TRIBE VII. --MARATTIEAE.
Gen. XXXV. Marattia. Sori of very curious structure placed at the ends of the veins, just within the margin, and consisting of two opposite, parallel, plates which are marked within by transverse
[Image of page 14]
Tribe VIII. Gen. XXXVI, XXXVII.
gashes, opening into as many cells which contain the spores. These sori have very much the appearance of so many carraway-seeds. 1 Species.
TRIBE VIII. --OPHIOGLOSSEAE.
Gen. XXXVI. Ophioglossum. Frond thick, juicy, simple; fructification on a flattened spike distinct from the barren frond. 1 Species.
Gen. XXXVII. Botrychium. Frond thick, juicy, tri-pinnate; fructification in a large, many-spiked cluster at the end of a long erect stalk. 1 Species.
