CHAPTER I. Explanatory.
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Ferns of New Zealand.
ALTHOUGH the ferns of New Zealand have long been proverbial for their beauty and variety, no work has yet been published professing to treat of them alone. They have been classified and described by Dr. Hooker in his "Flora Novae Zealandia," and they are also mentioned in several books on ferns, but these works are too voluminous and expensive to suit the means of many, so that whilst the collection and preservation of these beautiful plants has become a popular amusement, few can name or classify their specimens. The following pages have been written with the desire, in some measure, to supply the means by which those who at present collect ferns without any knowledge of their botanical names may add to the pleasure of their pursuit by the systematic arrangement of their acquisitions: The use of scientific terms has been, as far as possible, avoided, and complete botanical descriptions must not be sought for in this pamphlet, but no fern hitherto found in the Islands has been left unmentioned, and it is hoped that the characteristics given of each will be sufficient to enable the enquirer to identify and arrange them.
It will perhaps be well to commence our subject by finding out the place that ferns take in the entire system of botanical classification, and their relation to the rest of the vegetable world.
De Candolle distributes all plants into three great classes, --Exogens, Endogens, and Acrogens; plants belonging to the last of these classes have no wood, or wood having a sinuous structure, no flowers, and bear reproductive organs called spores. Acrogens again are divided into sub-classes Foliaceae and Aphyllae, the first comprehending those that have, the second those that have not, distinct stem and leaves, and in the first of these subclasses we shall find the natural order Filices (Ferns) with this essential character:-- A distinct stem and leaves, the latter usually divided into numerous pieces, and marked with veins either simple, forked, or anatomosing. Vernation circinate. Reproductive organs either upon the back or margin of ordinary leaves or wrapped up in, or covering separate and contracted leaves.
Thus we arrive at a clear definition of our subject and find that, of the three great classes that comprehend all plants from the most stately tree to the minutest sea-weed, ferns belong to the third; and further that they form the first Natural Order in
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the first of the two sub-classes into which Acrogens are divided. The number of known living species of ferns has been estimated at 2,000, and of fossil ferns there are some hundreds already known of species entirely distinct from those now existing. Of these it may be added for the information of any one who may be travelling in that direction that Dr. Hochstetter mentions "a locality on the West Coast, about 7 miles south of Waikato Heads, where beautiful fossil ferns are imbedded in grey argillaceous strata alternating with sandstone layers and small coal-seams."
The distribution of species is remarkably wide, and this, as well as another fact, to be hereafter mentioned has led to great confusion of nomenclature. Thus, a local botanist, finding a fern new to him, bestows upon it a name and when it has gained some currency, it perhaps falls into the hands of one better informed on the subject, who forthwith shows the plant to be one which has already, received two or three names from presumed discoverers in various parts of the world. In this manner, 1 one of the New Zealand ferns has received no less than eight different names! Dr. Hooker comprises 117 species in his Flora Novae Zealandiae, of which he says, 30 are of such wide distribution that they may be termed cosmopolitan or mundane; 30 inhabit South America; 61 Australia and Tasmania; 10 are European; several which are not known to be natives of Australia or America, have been found in the lofty mountains of Java; and others in South America. Still he gives 42 as peculiar to New Zealand, although it is not unlikely that they may yet be found common to other parts of the world. Since the publication of his work several other species have been discovered in these islands.
Before proceeding further, it will be necessary to become acquainted with the names of the various parts of ferns; and also with a few botanical terms, the use of which we have been unable altogether to avoid. The rhizome is the underground rooting stem; the stipes is the stalk from the ground up to the commencement of the leafy pert; the continuation of this stalk is called the rachis; the principal veins branching from the rachis are costae and those branching again from the latter are termed costules, veins, or veinlets; rhizome, stipes, rachis, costae and costules forming as it were the skeleton of the fern. When the veins do not branch they are simple; when they branch and the branches do not meet or run into one another they are forked and free; when they branch and unite again so as to form a network they are anastomosing; in such case the spaces between the veins, within their meshes, if we may so speak, are termed areoles. The whole leaf is called a frond, its primary divisions are pinnae; and
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when the pinnae have distinct leaflets these are pinnules: segments and lobes are terms indifferently applied to the projecting parts of notched fronds, pinnae, and pinnules; the recess between lobes is a sinus. A frond is pinnate when its pinnae are quite separate from each other; when they unite before reaching the rachis: the frond is pinnatifid; bi-tri-pinnate and bi-tri-pinnatifid are terms applied to fronds which are thus divided twice or thrice, their pinnae and pinnules being more or less deeply cut in like manner with the frond itself: when a frond has neither pinnae nor pinnules it is simple. Each of the little masses of fructification 2 is a sorus, and generally consists of a number of capsules which in their turn contain spores--the microscopic reproductive organs. The capsules are sometimes surrounded wholly or in part by an elastic ring or annulus, a microscopic feature in most ferns; but in others, especially in some of the tree-ferns, distinctly visible with the aid of a pocket lens, and bearing the appearance of a spiral wire spring of exceeding fineness and beauty. In some species the capsules are placed on a receptacle elevated from the surface of the frond, and they have also in many cases a covering which varies in form and substance, and is called an involucre 3 when this is wanting the sorus is said to be naked. By means of the growth, arrangement, and absence or presence, of these different parts, the order Filices has been divided into tribes, genera and species: a gradually narrowing circle, one tribe often containing many genera; each genus, many species; and great variation even being sometimes observable between individuals of a species. To this last point we would particularly draw the attention of our readers: each species is generally supposed, (although there is great difference of opinion upon the subject,) to have proceeded from its own parent plant, but often, from difference of climate, soil, or situation, individuals of a species vary considerably; so that when ferns, although apparently very different, are apt to revert to one original type; or when specimens have been found which by a series of extremely close links unite each other to some particular species, they are only considered varieties as they may well be referred to a common parent plant. Many ferns varying in this way have received names as new species; and one only partially acquainted with botany is very apt to make this mistake, as the varieties which complete the chain are often found in far distant localities. Thus, Dr. Hooker observes, that before he could define the characteristics of Lomaria procera, "whose varieties to an unpractised eye are more dissimilar than other species of the same genus," he had to examine many hundred specimens of that plant gathered not only in New Zealand, but in Australia, South Africa, and South America.