The ferns and fern allies of New Zealand, with instructions for their collection and hints on their cultivation

Front matter

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Preface

CuapterR J.—THE STRUCTURE OF FERNS AND ALLIED PLANTS

Carter II.—NOMENCLATURE AND PRINCIPLES OF CLASSI-

FICATION

Cuaprer II].—ENUMERATION AND SPECIFIC DESCRIPTION

Cuarter IV.—HINTS ON COLLECTING AND CULTIVATING...

GLOSSARY OF SPECIFIC NAMES

Index

PLATES.

PREFACE.

Tue demand for a compendious and handy description of the Ferns of New Zealand has led to the publication of more than one little work on the subject ; but from one cause or another these books have rapidly passed out of print, so that the collector—desirous of identifying the plants he obtains—is obliged to consult Hooker's “ Handbook of the New Zealand Flora,” a work which is too general in its outline for his purposes, and which is already somewhat out of date. To satisfy this demand, the author has been led to prepare this small manual, in the hope that it will meet the requirements of the case and will prove to be longer-lived and of more lasting value than its predecessors.

The usual demand in such a work is that it shall be written in a “popular” style and in “popular” language—in other words, that all technical terms shall be avoided in descriptions. Books of this class are in the majority of cases unsatisfactory, usually lacking that scientific accuracy which is the first requirement of such works, but chiefly being defective in conciseness of description and exactness of phraseology. They fail to satisfy those who want scientific descriptions, and are not sufliciently explicit for those who have little knowledge of the subjects treated of. A large technical vocabulary has grown up round the literature of ferns, which it is impossible to ignore altogether. No one can lay claim to a knowledge of these plants without knowing something also of this terminology ; for it is impossible to examine ferns without finding characters and points of structure which our ordinary vocabulary fails to describe aptly. There is hardly any pursuit or study which has not a terminology of its own, and the student of ferns will find that there is such a terminology in his branch, and that it has to be mastered before he can make satisfactory progress in the identification of species. The author has therefore deemed it advisable to write the descriptive viii PREFACE.

part of the work in technical language, avoiding, however, all unnecessary multiplication of terms; and at the same time—by a clear introductory chapter on the structure of ferns and their allies, and by the aid of a complete glossary—to enable the reader to understand every term used. There is no serious difficulty in, mastering these terms, as a little patient application will prove, and there is no satisfactory way of avoiding their use without sacrificing the scientific value of the descriptions. If any are afraid to enter upon the study of our ferns because there are some apparently hard names to be got over, we would advise such persons to turn their attention to something else. If the subject is worth studying, no one need grudge taking a little trouble about it.

In the preparation of this work, every available source of information on the subject has been consulted. While differing on some points from those whose labours he has availed himself of, the author has to acknowledge the very valuable assistance which he has received from various sources, and chiefly from the writings of Messrs. Colenso, Kirk, Cheeseman, and Potts—botanists who have done much to bring about the present well-advanced state of scientific knowledge in this young country.

Dunepiy, January, 1882.

THE FERNS AND FERN ALLIES OF NEW ZEALAND.

Chapter I. The Structure Of Ferns And Allied Plants

Wuat isa Fern? The question is often asked, but it is not always easily answered, at least in a manner satisfactory to the questioner. It will not enlighten the majority of inquirers to say that—‘‘ A fern is a vascular cryptogam, bearing well-developed leaves which have usually simple or forked veins, are circinate in vernation, and bear sporangia almost always collected into sori on their under-surfaces or margins.” While, no doubt, perfectly true and quite satisfactory to the botanist, this description might—as far as its general application is concerned—be couched in Greek. It will be advisable, therefore, to explain what the above definition means, and in doing so we shall hope to give an explanation which will be comprehensible by those who know nothing of botany.

The majority of our cultivated plants bear their organs of reproduction in tolerably conspicuous groups, which we call the flowers and fruit. A single flower, like that of the strawberry, for example, contains a large number—probably from 50 to 100—of these reproductive organs, and they are called respectively the stamens (male organs) and pistils (female organs). By the fertilizing action of the former on the latter, the seeds are developed. When the other parts of the flower have fulfilled their functions, the pistils continue to increase in size, forming the fruit which we see when ripe as little seed-like bodies (popularly known as the seeds) on the outside of the succulent strawberry. These contain the true seeds, which, when sown, give rise by direct growth to similar plants to the one which produced them. All flowering plants are furnished with stamens 2 and pistils ; and as these are generally visible to the naked eye, the whole of this large class of plants is included under the general term of Phanerogams (Gr. phaneros, evident), or plants with conspicuous organs of reproduction.

But there is another still larger class of plants which have no stamens and pistils, and whose reproductive organs are in many cases so minute that the aid of the microscope is required to bring them to our view. To this class belong Ferns and their allies, Mosses, Mushrooms, Lichens, Seaweeds, and numberless allied forms, and they bear the general name of Cryptogams (Gr. eryptos, concealed), or plants with inconspicuous organs of reproduction. These plants produce, in different parts of their structure, minute reproductive organs termed generally spores. When we shake a dried fern-frond, we frequently shake out a cloud of these in the form of a fine brown dust. If the fresh spores of a fern are placed under suitable conditions of moisture and warmth, they germinate and give rise to a cellular growth, like a miniature seaweed, called a prothallus. This prothallus—which, in the case of most ferns, is not more than 75th to gith of an inch in diameter—is formed of several cells usually arranged in a more or less plate-like manner. It is furnished with root-hairs, but is without a distinct stem or leaves of any kind. On this miniature and short-lived plant, true sexual organs are produced which, after fertilization, give rise to a second plant—the true fern-plant. All the plants allied to ferns have the same general mode of reproduction, so that in this whole group we notice what is termed an ‘alternation of generations.” ‘The first of these is asexual, the spore giving rise to a prothallus ; the second is truly sexual, and produces a fern-plant similar to that from which the original spore was developed.

This alternation of generations is a primary distinction between Ferns and Flowering Plants—because though probably it occurs in the latter, still it is at such an early stage of the development of the seed, that botanists have not succeeded in fully detecting it.

Again, from the lower orders of Flowerless Plants, Ferns and their allies are distinguished by many characters which testify to their much higher state of development. The most manifest distinction is that of possessing woody tissue in their stems—this being absent in all the other cryptogams.

But really to understand fully the meaning of our first technical definition, and to obtain a clear idea of the structure of the different parts of ferns and note the application of the various terms applied to them, we cannot do better than take a few growing specimens of some common kinds and examine them in detail. We can then compare them together and note the similarities and divergences of their structure. I often hear the remark ‘‘I am very fond of ferns, and like to gather and press them, but I don’t know anything about them, you know, as to their names and that sort of thing.” If anybody is really fond of ferns, such an one will not grudge a little trouble to know something about them, and I can assure my readers that any trouble taken for such an end will more than repay itself in the increased zest and pleasure it will bring with it.

For the purpose of our first examination then we will take three very familiar ferns, which anyone will be able to distinguish, and which can be obtained in almost every part of New Zealand. These are figured on the frontispiece, and are Polypodium billardieri (fig. A), a common climber on trees; Lomaria fluviatilis (fig. B) and Asplenium bulbiferum (fig. C), the two latter being terrestrial ferns.

Let us examine the Polypodium first. The stem (fig. A 1)—known as the rhizome, from its root-like appearance—is many feet in length, and as thick as one’s little finger, and is covered with closely-pressed brown scales. It bears at irregular intervals the leaf-like branches, technically called fronds, but more commonly the leaves. The stalk which forms their lower part (fig. A 2) is called the stipes, while the continuation of it through the flat green lamina of the frond (fig. A 3) is the midrib or costa, from which again veins and veinlets branch. In the plate the arrangement of the veins cannot be made out, but it is a very prominent feature in the fresh fronds. The veins are seen to diverge from the midrib nearly at right angles, then to branch into two, and these to branch again. In the spaces between the main veins—termed the areoles—the fine veinlets are seen to disappear in the texture of the frond. A representation of this mode of branching is shown in Pl. IIT. fig. 7, where a portion of one of the fronds of this fern has been drawn. The frond is either all of one piece with continuous uncut margins (as in fig. A 3) when it is simple, and its margin entire ; or it is more or less cut into. Thus in fig, A 4, the blade is cut into numerous long narrow divisions or lobes, but as the cutting does not extend to the midrib, the blade is still all of one piece and therefore simple. It is, however, said to be pinnately lobed, and the correct term to apply to it is pinnatipartite. Had the incisions extended only about half-way from. the extremity of the lobes to the midrib, the leaf would have been termed pinnatifid. In describing the shape of such a frond, an imaginary line is drawn round the tips of the lobes, so that the general shape of the outline is given; in this case it might be described as broadly elliptical-ovate. The frond A 3 is linear, as arethe lobes of A 4, while the apices of both fronds are acuminate. At the left side of the rhizome a small entire frond is figured, which is: linear-oblong in shape with a sub-acute apex, while the very small frond on the extreme right is also linear-oblong, but with an obtuse: apex.

On the back of the mature fronds, and placed on the secondary veins, are two rows of orange-brown spots, varying from +,th to tly of an inch in diameter, commonly known as the seed, but called by botanists the sori (sing. sorus). These sori are groups or collections of the reproductive organs, and their presence on the back of a frond is one of the chief points of difference between fronds and ordinary foliage leaves, as the latter do not—in flowering plants at least— bear these organs, If a single sorus is examined—and here the aid: of a good magnifying lens will be needed—it is found to consist of a number of minute oval bodies (the capsules or sporangia, see PI. I. fig. 4a) joined by a short stalk to the frond. These capsules arenearly surrounded by a jointed ring or band (the annulus), which passes vertically over them, and which, by its elasticity, serves torupture them when mature. The bursting of each capsule liberates: a number of minute rounded or triangular bodies—the spores—which fly out as a fine dust. This dust is frequently spoken of as fern-seed, but the term is quite incorrect, as a spore is not a seed, but is more: comparable to a miscroscopic bud.

If we now take Lomaria fluviatilis (fig. B), we shall find the same parts, but with very considerable diversity of form. Here the rhizome (fig. B 2) is short and erect, being rendered thick by the bases of old stipes which remain attached all round it, while the fronds stand in a tuft from its upper end. Such a rhizome is often called a rootstock ; and-though so different in length and appearance from that of the Polypodiwm, it is yet a similar organ, only very much contracted. The fronds, also, are very different in appearance, and are distinctly of two forms (hence called dimorphic) ; one of these (fig. B 6) being the sterdle or barren fronds, and the other (fig. B 5) being the fertile, or spore-bearing. The function of the barren fronds being chiefly to aid in the nutrition of the plant, they are tolerably large and well developed, while the sterile ones are reduced to the smallest size compatible with the production of the numerous Spore-capsules developed on them. Instead of having a single blade, or lamina, on their short stipes, both forms have a number of separate small blades or leaflets (the pinne) arranged along the midrib of the frond, which is in this case called the rachis. This rachis is not smooth and polished as is the stipes of the Polypodiwm, but is clothed throughout with slender, pale-brown scales. The pinne, which are either opposite or alternate with one another, approximate together till at the very apex of the frond they are in close contact, and their bases are said to be decwrrent, as they form a wing on the rachis. A frond bearing such pinne is said to be pinnate, except at the very top, where—the leaflets having become continuous—it is only pinnatifid. The separate pinne in the right-hand frond are oblong in shape, while the broadest of those on the left are broudly-elliptical ; both have their margins minutely toothed. If we examine the underside of one of these pinne, we notice a midrib having a few scales on it, and from it a number of fine veins branch, each of which divides almost at once into two equal and nearly parallel arms, like the two branches of a tuning fork. This mode of branching in two’s, whether it occurs in veins (Pl. IV. fig. 2) or in the branches themselves (Pl. IV. fig. 1), is termed dichotomous. No traces of sori are to be found on these pinne, and the frond is therefore termed sterile. :

The other fronds of this same plant (fig. B 5) are very different in appearance, owing to the pinne being extremely narrow, and to their standing almost parallel with the rachis. On turning up the underside of one of these pinne, it will be seen that the margins are turned back very completely, and in the hollow thus formed the capsules are crowded in a dense, continuous line. The recurved edge of the frond thus forming a covering to the confluent sori is termed the involucre or indusiwm. (An enlarged section of the sorus and its involucre, as it occurs in another species—viz., L. banksii—is shown in Pl. II. fig. 86.) So closely do the recurved margins of the pinne and their included capsules come to each other, that all trace of the venation is hidden; but it is on the extremities of the closely-approximating veins that the sori are placed. The spore-capsules and their contained spores are so similar in general appearance in the three ferns chosen, that we need not here refer to them again.

Our third example, Asplenium bulbiferum (fig. C), differs from both of the others in many points, and agrees in many others. Owing to the great size of the specimen selected, only a portion of the frond—which when complete was nearly 3 feet long—has been represented on the frontispiece. The rhizome is short and thick as in the Lomaria, and more or less scaly, while the fronds stand in a tuft at its apex. In them there is not. the same separation into sterile and fertile, but all are nearly similar, and when mature are spore-bearing. And here we may note, that the young fronds of all ferns have a very different mode of unfolding from ordinary foliageleaves. They are rolled up from the apex to the base in the form of a crozier, and their vernation—i.e., the position occupied by them while in bud—is said to be circinate.

The mature frond is furnished with a stipes and rachis (which is often dark-coloured on its upper side), but this, instead of bearing pinne, bears a secondary set of rachises, and these again a third. In the upper parts of the frond, however, the secondary rachises only bear leaflets. In such a frond, the secondary rachis and all that it bears constitutes the pinna, the tertiary rachis and parts form a pinnule, while the further subdivisions are the lobes or segments. A frond with pinnules arranged along its secondary rachises is 2-pinnate or bipimnate ; if its pinnules are again cut into separate parts, it is 3- or tri-pinnate ; and if still further subdivided it is decompound. It is often a matter of considerable difficulty deciding what term ought to be applied in describing the extent to which the division of the frond is carried, owing to the fronds being cut almost to the rachises, but having these winged in many cases with a portion of the lamina. Thus some ferns are said— in the “Synopsis Filicum”—to be 2- or 3-pinnatifid, which are described as 2- or 3-pinnate in some other works. The rule here ought to be that where the blade is distinctly interrupted into separate pinnze or portions, the term pinnate, or 2- or 3-pinnate, should be employed; but if the portions are united by continuations of the lamina, the frond is still a simple one, and the term pinnatifid should be adopted. It will still be found, however, that the application of the rule is by no means easy, as many ferns are pinnate below and pinnatifid above, and nothing but practice and good observation will enable anyone to apply the correct terms.

The venation of our Asplenium is seen to be different from that of both the others examined, the midrib which traverses each pinnule sending out single unbranched veins alternately to each of the lobes or to their ultimate segments. Along one side of each of these veins, and placed obliquely to the midrib, is attached a slender, elongated, pale-coloured membrane—the involucre—covering the linear sorus. When the spores are mature, this ruptures along the side next the margin of its segment, and discloses to view the sorus formed of a dense line of closely-crowded capsules. Near the extremity of many of the segments of this fern small swellings or outgrowths, bearing a few very young leaves, may be noticed. These are the bulbis or gemmee, from the presence of which the species received its second name—bulbiferum, or bulb-bearing. Plants bearing such bulbils are said to be proliferous. If these little growths, together with a small portion of the frond to which they are attached, be removed and planted in fine, damp soil, they will grow into new plants.

If we now seek to apply all the terms we have learned to other ferns, we shall find that the same organs show many diversities of structure besides those afforded by our three selected examples. We shall consider the parts in the order already followed.

The rhizome in many species is very much elongated, creeping underground in some, as in the common Bracken (Pteris aquilina), or above-ground, as in one of our commonest Maidenhairs (Adiantum affine). ‘In tree-ferns it is elongated into a more or less erect trunk or caudex, the upper part of which is often clothed with the bases of the stipes of old and withered fronds, while the lower portion is usually thickened by root-fibres. Between the long creeping or climbing rhizome of some species, and the stately trunks—often 20 to 40 feet high—of some of our handsomest tree-ferns, a nearly continuous gradation may be noticed.

The stipes varies in different species chiefly in its relative length and thickness, and in the presence or absence of scales and other appendages.

But it is in the fronds that the most conspicuous distinctions are to be found, in their size, form and texture. They vary from not more than about half-an-inch in length (as in Hymenophyllum cheesemaniz) to as much as 20 feet in the giant Mamuka (Cyathea medullaris). Some are quite simple in form, while others are cut into innumerable little segments. In many Hymenophyllums (filmy-ferns) the texture is more delicate than tissue-paper, and the tissues are formed of a single series or layer of cells; while in Polypodiwm serpens the consistence is that of leather. The surface is also very variable; being glossy and quite destitute of hairs (glabrous) in many species, or in others variously clothed with hairs or scales of extremely different lengths, coarseness and abundance.

Among the most characteristic features in ferns are the shape and position on the frond of the sorus or collection of capsules, and the presence or absence of its énvolucre or covering membrane. We have already seen that they are sometimes round and placed on the back of the frond, or linear and close to the margin, or are ina continuous line round the margin. In the Polypodiwms they are naked, having no covering of any kind, while in Lomaria and Aspleniwm they are seen to be furnished with some sort of an involucre or indusium. The structure of this covering is very various, but we can only consider it as it exists in a few genera. (For its many modifications, the reader must be referred to Chap. III.) In some cases, as in the Aspidiwms, or Shield-ferns, the involucre is a small circular disc fastened by the centre of its under surface to the middle of the sorus (Plate ITI. fig. 3a), and it is from this shield-like mode of attachment that both the scientific and common names of these ferns are derived, In the allied genus Nephrodiwm the involucre is kidney-shaped, but otherwise similar. In these, and in Aspleniwm, the involucre is a specially-developed structure of the epidermis of the frond. In Hymenophyllum and its allied genera it appears to be an outgrowth of the tissue of the frond itself. In them the veins are produced beyond the margins of the frond, and the capsules are clustered near their extremity, and covered by a 2-valved involucre, the lips of which open outwards (Pl. I. fig. 76). This prolongation of the veins is termed the receptacle ; in the true filmy-ferns it occasionally protrudes beyond the lips of the involucre, when it is said to be exserted. In Loxsoma (Pl. I. fig. 6a) and in Trichomanes (PI. I. fig. 8a) this receptacle is usually very considerably exserted, and the involucre is still further modified into a long narrow tube or cup.

In Adiantum (Maidenhair) (Pl. IT. fig. 3), Hypolepis (Pl. II. fig. 4), Lomaria, and many other genera, the involucre is often termed a false one, being the result simply of the margin of the frond being turned or rolled back over the sorus. One of the most anomalous forms is to be found in Marattia, in which the capsules are united into boat-shaped groups, called Synangia (Pl. IV. fig. 2a), Until the development of these peculiar sori has been fully investigated, we cannot decide how they are formed nor what relation they hold to the sori of other families of ferns. So different are they in structure and development that Sachs considers that the whole family to which this genus belongs should be removed from the true ferns, and classed, together with the Ophioglossacee and Equisetacez (horse-tails), in a separate group or order by themselves.

The only other point we need to note here in regard to the external form of ferns is the shape and structure of the capsule (sporangiwm) itself, and the position of the ring. The former is formed of a single layer of cells arising from the outer skin or epidermis of the frond, and the ring isa layer of the same group of cells somewhat modified in form. The capsules vary in form, some being globular (G@leichenia, Pl. I. fig. la), others pear-shaped (Polypodium, &e.) ; but it is the position of the ring which is the most marked feature in them. This constitutes, in fact, the most distinctive character by which the tribes of ferns are separated from one another ; but as it is detailed in full in Chap. IIL, it is not necessary to go into much explanation of ithere. Itis worth noting, however, that when the annulus is transverse (as in Gleichenia) or oblique (Cyathea), or when it forms a cap on the top (Schizea), then the opening or dehiscence of the capsule is necessarily longitudinal ; while, if the ring is vertical, passing over the top of the capsule, the dehiscence is transverse. This is found in all the tribe of the Polypodiacez, to which by far the largest number of our ferns belong.

In many ferns, minute jointed hairs, called paraphyses, occur among the capsules.

I have said nothing in this chapter of the general structure of the fern allies, because to do so would occupy too much space in a work which is chiefly devoted to ferns. But in the following chapter I have shortly described the most characteristic features of their orders, while in Chap. ITI. all the species to be found in New Zealand are treated of in detail.

FERN ALLIES OF NEW ZEALAND. 1k

Chapter II. Nomenclature And Principles Of Classification

Aut plants, when scientifically described, have two names given to them ; the first of these is the generic name, or that of the genus to which the plant belongs; the second is the specific name, or that of the particular species of plant. This binomial nomenclature—or giving of double names to plants—was one of the many revolutionary changes in the march. of scientific progress which we owe to the celebrated Swedish naturalist Linneus.

The generic names (of ferns at any rate) are usually derived from the Greek ; and, in giving such names, botanists have often been guided by very fanciful considerations. The name most commonly used among the genera of ferns is Pteris (Gr. pteron, a wing), originally given by Linnzus to the common Bracken. This being one of the commonest of ferns, the name has come to be used very frequently as synonymous with the name fern. Besides the genus. Pieris itself, we have, however, only one New Zealand genus into whose name this term enters, viz., C'ystopteris or Bladder-ferns.

The specific name is commonly of Latin origin, and is often expressive of some characteristic feature of the plant (e.g., hirsutum), or of its habit (scandens), or of the locality where it occurs (¢unbridgense), or it may be given in honour of some botanist or collector —usually the first discoverer of the plant (cunninghamit). It is usual to commence the generic name with a capital letter, and the specific name with a small letter, even when it is derived from a proper name.

Frequently the same fern has been found in different countries, and named by different botanists, whose descriptions may have been published in any one of the numerous British or foreign publications brought out so abundantly during late years ; and thus it comes to have two or more names. Or the same botanist may have obtained two or three varying forms of the same plant; these he describes under different names as being distinct species, and then someone else, examining these species, comes to the conclusion that after all they are only varieties, and he accordingly disallows all the names but the first. As we shall see further on, there is great confusion in the minds of many botanists as to what a species is, and hardly any two can agree as to where the line between species and varieties is to be drawn. Many very celebrated botanists are in favour of reducing the number of species by widening their limits, while others look upon comparatively slight variations as of specific importance. In this last category the majority of cultivators and collectors of ferns, and horticulturists generally, must be included. One result of this difference of opinion is that some favourite kinds of plants have had so many names given to them that systematic botanists have great difficulty in clearing up the confusion: which exists. Ferns have probably suffered more in this respect than any other plants, owing to their having been so long collected and cultivated, and also to the wide geographical range of many of the species. The rule for settling this difficulty is a simple one, the first name given being entitled to priority, and being distinguished by having appended to it the name—or a portion of the name—of the botanist who described it; for example, Pteris aquilina, Z., informs us that Linneus was the author of the name. Any later name given to this fern ranks only as a synonym. The application is by no means so simple as the rule itself, and often, in spite of great care, extreme confusion has crept into the nomenclature of ferns, to remain until someone has had the courage to face the difficulty, and reduce the chaos to something like order. The work which has done more than any other to effect this is probably the ‘‘ Synopsis Filicum” of the late Sir W. Hooker and Mr. J. G. Baker, of Kew. In New Zealand, we are indebted to Mr. Kirk for some valuable work of the same kind.