OUR COLONIAL FERNS

New Zealand Illustrated Magazine, Volume V, Issue 3, 1 December 1901, Page 198

OUR COLONIAL FERNS

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Illustrated by reproductions from the author's book, " The Ferns of New Zealand"'' TP%EW ZEALAND is celebrated for its ferns, of II 111 w hi c h) i" proportion to its size, it contains a - — 11 greater number and variety than probably any other country on the globe. It is only about equal in area to the United Kingdom of Great Britain and Ireland, yet while the latter contains only forty-one kinds, distributed in fourteen classes, New Zealand has about one hundred and fifty kinds, in which no less than thirty-three classes are represented. This great wealth of ferns arises from the length of the colony, from north to south, in proportion to its width, and from the height of its mountains, the result being a diversity of climate, ranging from sub-tropical near the coast line in the extreme north to sub-Arctic near the perpetual snow line in the south. Thus we have ferns ranging in height from less than half an inch to the gigantic tree ferns, towering aloft to an altitude often of fifty feet, and occasionally to over one hundred feet in rich deep gullies. They vary also from the simplest and lowest forms to the highest and most complete. Very many of our colonists take more or less interest in ferns, and this seems particularly the case with dwellers in towr, who, on going into the country, frequently bring back some of these beautiful plants, which they generally fail to grow, owing partly to their not having noticed the conditions under which the ferns naturally exist, and endeavouring to imitate these conditions as nearly as possible, and partly to their damaging the roots by pulling them roughly out of the ground. Another cause of failure is the general use of gas in town houses, and yet another is overwatering. Perns in general need a moist atmosphere, but not too much water, particularly if planted in rich or retentive soil, for manure is generally poison to them.

How long ouv wealth of ferns will continue is questionable. Even now several kinds have disappeared from localities in which they were formerly abundant, and it is uncertain whether they occur elsewhere, and it is pretty certain that others will be lost,

From the author's book, "The Ferux of NVw Zealand." 1. Lonmria. procera '• Polypodiiim Billiirdien, Hiniplo frond, fertile In. „ „ . fertile frond. la. „ „ piunatilld frond, Imrrcu 2. Gleichenia circiniita *'>• .. »- »• « fortiio 3. Trichomunes reniforine

as our forests get destroyed, and sheep and cattle eat the hearts out of them. Thei'e were doubtless many more kinds in Europe formerly than there are now, and the same will happen in New Zealand, which is greatly to be regretted, as these plants are most interesting in various ways. For example, the propagation of them is particularly interesting, because it exhibits the carious natural pheuomena of what is scientifically termed " alternations of species " : that is an organism assuming different forms alternately. As many of my readers are probably unaware of this fact, it may be well to mention a very noticeable case of it. Those who have been at the seaside in early autumn will probably have observed what are generally called "jelly n'sh," round masses of apparently gelatinous substance, with a bunch of fibres of similar texture hanging beneath each. Each one has a round cavity in its centre, and as it floats about it expands and contracts, as if breathing. In the same way visitors to a rocky coast will have seen what are called "sea anemones " growing on the bottom of the pools among the rocks. These look like beautiful blossoms, consisting of numerous petals of all shades of red, yellow, and purple, surrounding and radiating from a central cavity, the whole being supported on a stalk two or three inches high. The non - scientific observer, however, will probably never dream that jelly fish and sea anemones are merely different forms or stages of the one organism, yet this is actually the case. The jelly fish, when mature, sheds germs, which float about and develop into jelly fish, and a similar alternation actually occurs in the case of ferns. Ferns grow from tiny germs called " spores," smaller than the finest pai'ticles of flour, and so light that they are wafted by the wind to long distances, and when a spore falls on a suitable soil, it begins to grow, sending down hair-like roots, and producing other cells all round it, till it looks like a flat green scale lying on the ground, yet held down by its root hairs.

After ;i while male and female organs are produced among the root hairs. The female oi'gans are deep cup or vase-shaped objects, with a tiny germ inside the bottom of each. The male organs ai'e globular capsules, and these, when matured, open and discharge what are called spermatozoids, little things like tadpoles, with round heads and one or more tails, by means of which they wriggle about from place to place. On finding a female organ, a spermatozoid at once enters it, and fertilises the germ lying within it, on which the germ begins to grow, and gradually develops into a fern.

Another thing which makes our ferns extremely interesting is the evidence which they afford as to the soundness of the evolution theory, there being a regular series of forms from low and simple to high and complex. The spores are contained in globular or pear-shaped capsules furnished with elastic rings, which burst themselves open when mature, and scatter the spores abroad. These capsules are always situated on veins ou the underside or mai'gin of the fronds, aud in the lowest classes stand alone, though in some of the higher Gleichenias they occur in groups of three or four together. In the Polypodies they become numerous, and form round or linear masses. In Alsopliila they are so numerous and grow so close together that the under surface of the froud rises into masses to make room for them. In the higher Polypodies these mounds become actual columns or ridges called "receptacles," rouud or at the sides of which the capsules are arranged ; as it is obvious that, under such circumstances the capsules would be exposed to injury, Nature provides for their protection in various ways, and it is according to the nature of this protection that ferns are classified. Thus in Schizcea, Botrychium, and Ophioglossum the capsules grow closely together for mutual protection. In Loxsoma and Hymenophyllum scales grow up and enclose the capsules and receptacles between them. In Trichomanes this protection, which is called an involucre or indusiitm, becomes vase - shaped. In

From the author's book, " The Perns of New Zealand." 1. Gleichenia dicarpa 3. Neiihrodium lmimliiin 2. Hypolepis nullefolia I- Alsophila Colennoi, two j»iunoo

Aspidium the scale is for mod on the top of the receptacle, and covers the capsules like au umbrella. In Dicksonia, Hypolepis, Lomaria, Fteris, Gleichenia dicarpa, the edges of the lobes of the frond turn over so as to cover the capsules. In Lindsaya the edges become double with the capsules between the folds. In Nejphrodium and Nejphrolepis the receptacle is towards one side, and the protecting scale becomes kidney-shaped instead of like an umbrella. In Athryiwn the whole arrangement partly straightens, and in Asplenium becomes quite straight. In Gyathea, Hemitelia, and Dichsonia the capsules are enclosed in globular coverings which, when ripe, burst open horizontally or transversely, so as to allow the capsules to discharge their spores. In Allantodia the covering is elongated into a curved cylinder with rounded ends (whence the name, which is taken from the Greek word allantos, or sausage), which opens longitudinally along the top, and in Marattia the sorus consists of a row of pits in which the capsules grow. The lowest and most complete forms grow on the poor volcanic soils, and the higher forms appear as the soil increases in richness owing to the accumulation of vegetable mould. Thus the evolutionai'y sequence is very complete, and such as to convince all but the most bigoted opponents of the theory.

It would be impossible, in the limited space of a magazine article, to give anything like full particulars of our colonial ferns ; but several books have been published respecting them. The first was written on behalf of an Auckland Church Building Fund, and was the work of a lady, though it was generally understood that the late Rev. W. Colenso supplied the information. The second was also by an Auckland lady, whose name I forget at this moment. The third was by Mr. G. M. Thomson, Science Master at the Dunedin High School; and the last, which was published eleven years ago, was by myself, and contained plates of all that were then known, with the exception of one which seemed to have disappeared from the only place where it was reported

as having been gathered by Mr. Forster, the naturalist who accompanied Captain Cook. Several others have been discovered since my book was published, and particulars of them appear in the annual volumes of the Transactions of the New Zealand Institute, and will probably be mentioned in a further paper in this Magazine. It was at first intended to print the plates in my book by ehrcmo-lithography, and the fern specimens were therefore arranged according to their natural colours, instead of according to their classes, but it was found that this would make the book too expensive for most peoples' means, and therefore the printing was done all in one colour, but the references to the plates at the head of the description of each kind of fern will enable the fern to be identified. The book also contains advice as to growing ferns.

Though so much has been written respecting oar ferns, there is still much to be learnt. In my book I adopted the classification of the Synopsis filicum, the recognised authority on the subject, but I cannot say I was altogether satisfied with it, as I believe that some plants which it treats as merely divei'gent forms of our species are really distinct kinds which should be separately classed. I have also reason to believe that we have more kinds of tree ferns than have been classified. Several collectors have assured me that they have met with tree forms of plants which I know only as tufted or even creeping-rooted ones, and I therefore think that the ferns which they have seen are really different from those which I know by the same names. It seems unlikely that a fern would so entirely change its habit of growth, or if so, that, though I have gathered ferns throughout a stretch of the colony, extending from the Dunedin goldfield in the south to the Bay of Islands in the north, I should not have observed an indication of such a change of habit. I feel sure, too, that tree ferus called by the same name in different localities are really diffei'ent kinds. For instance, what is called Cyatliea Gunninqhamii about Wellington is known as Hemitelia Smithii

From the author's book, "The Ferns of New Zouliwl. 1. Tricbomnnes Annstrongii 0. Loiiiuriii iiit-nthraniiccii 2. Aspleniiun uinbrosum, vtir. piirvifoliuui 7. No])Urodiuiii • le<'om|>OKitiiiii 3. Hyinenopliyllum Clieesemannii 8. Tficlionmiies luiniilo 4. Trichomnnes Lyallii !>. I'olyiiofliiini hoi'ikiiim 5. Hymenophyllum ranim

at Dunedin; and what is known by the same name at Auckland is quite different in its growth and appearance. Some years ago T saw some tree ferns in the upper part of the Horokiwi Valley, near Wellington, which seemed quite different from any which I had seen elsewhere ; but as I was in a coach, and the trees were probably one hundred yards distant, I had no chance of examining them. In my book I have mentioned a solitary tree of a Hemitelia, which I saw in the Mangawhero Valley, and which I have included as a form of Smitliii, though I am not sure that it was not a distinct plant ; and at Hay's Nursery, near Auckland, I saw a tree fern which I was told was a NewZealand plant, but which was quite different from any which I ever met witli in our forests, which I have traversed at all levels from the sea coast to the snow line on the mountains. There is therefore work for other collectors to do in clearing up matters such as these, as well as probably some kinds to be discovered, which have not yet been identified and classified. I mention these things becauso I am now too old to travel about and clear up such points, though I would gladly do anything in my power to assist in the work by examining specimens sent to me. Our ferns differ so much in appearance in different localities that a complete series of their forms would include some hundreds of specimens, and I often have peculiar fronds sent to me for report by persons who have not been able to identify them for themselves, or are doubtful as to what they really are.