Art. XXVIII.—On Abnormal Developments in New Zealand Ferns; with a List of Papers by various Authors on the Ferns of New Zealand.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 36, 1903, Page 334

Art. XXVIII.—On Abnormal Developments in New Zealand Ferns; with a List of Papers by various Authors on the Ferns of New Zealand. By A. Hamilton. [Read before the Otago Institute, 13th October, 1903.] Plates XXVI., XXVII. About ten years ago I was gathering specimens near the junction of Morison's Creek with the Leith Stream, and I noticed that the commonest fern in that particular part, Lomaria fluviatilis, showed several remarkable variations at the tips of the fronds, in the form of division and cresting. A few specimens were collected for my collection of dried ferns. A few months ago, however, I made a fresh visit to that locality, as I found that the City Corporation were intending to make this particular area the intake for an additional water - supply for Dunedin. I closely examined the area over which the crested fronds were found, and discovered a large proportion of the plants were growing on about a quarter of an acre. A large proportion of this space is covered by cuttings for a road up the creek and a road leading to higher ground. The face of these cuttings has received the spores of several species of ferns mainly belonging to the genus Lomaria—L. fluviatilis, L. discolor, L. lanceolata, and L. procera—with a few Asplenium and Pteris. The southerly exposure of the area was evidently favourable to the growth of fern-life, and there was sufficient moisture to insure quick growth. I endeavoured to obtain specimens of small young plants with crested fronds, but was not successful, except in the case of a stray plant of Lomaria lanceolata. In fully adult plants of L. fluviatilis, probably from ten to twenty years old, judging by the size of the root-stocks and the re-

mains of old fronds, it was easy to find many unusual and beautiful forms of cresting at the tips of the barren fronds. I took four large plants of L. fluviatilis and examined those fronds that were still green, with the following results:— Plant a.—Average length of frond, 30 in. It had twelve barren fronds, ten of which were crested, and six fertile fronds, three of which were crested. Plant b.—Average length of fronds, 15 in. The plant had eight barren fronds in sufficiently good condition to measure, and six of these were crested. The relatively small number of fronds is accounted for by the cattle having eaten off the tops of many, and having otherwise broken down the plants so that the condition of the apex could not be observed. Plant c.—Average length of frond, 19 in. There were seven barren fronds, and of these all were crested. Two fertile fronds were so far perished that it was impossible to say whether they had been normal or not. Plant d.—A large plant from a very wet situation, the average length of fronds 30 in. It had thirty-three barren fronds, of which twenty-four were crested, and sixteen fertile ones, apparently all normal. I cut this plant up carefully to see if the root-stock could be separated into separate heads carrying crested and non-crested forms separately, but found it only composed of three heads, each carrying crested and non-crested fronds. These results only show, of course, the proportion of abnormal fronds on the growth of the last season, or possibly two seasons. The dried and rotten fronds of previous years could not be examined as the tips perish so readily. A specimen of the form of cresting is shown of Plate XXVI. I have no doubt that such a natural sport could be perpetuated and improved upon by cultivation, as the sporiferous fronds have been found divided and crested. I have given several plants to a gentleman who takes an interest in the culture of New Zealand ferns, and he will, I hope, be able to perpetuate, if not improve, the variety. Since finding this form at Morison's Creek I have come across equally good specimens in deep creeks nearer the Waitati Saddle, in the Water of Leith, though not in such profusion. In thinking over the matter of variation in fronds I remembered noticing an unusual number of abnormalities in the fronds of the common Lomaria procera, which covers a large portion of the southern slopes of Signal Hill, and which seems to spring up after every scrub-fire, like the Pteris on the hills in the North. On the 3rd September I went out for two hours one afternoon on the hillside with the view of

gathering all the unusual forms that I could see. At that time of year nearly all the fronds of the past season are withered and frosted, and it is only under the high manuka or under the shelter of some rock or bush that fronds fit for examination can be found. I have tabulated the result of my foraging, and I find that I picked eighty fronds which did not appear to be normal. A very great proportion of all the fronds are what I shall call depauperate—that is, the margin of the pinnæ is highly irregular, instead of conforming to the shape of the pinnæ of the normal fronds. This is not peculiar to Signal Hill; the same obtains on nearly all high ground around Dunedin, and requires to be exactly described by an experienced botanical physiologist. Of these I picked a few here and there for future study. I should say that fully 70 per cent. of the fronds of Lomaria procera are thus affected. Another class of abnormal fronds is the case in which the main stipe is divided below the lowest pinna, and has practically two barren fronds on a single stipe. Another class, or perhaps a subdivision of the last, is where the stipe is divided nearer the apex, giving a partly double frond. The next variation is where the terminal pinna is divided once or many times; and, finally, where one or more of the lateral pinnæ are divided. Of the eighty fronds brought home there were: Depauperate, 11 (only a few of the most curious were picked); stipe forked below commencement of pinnæ, 15; stipe forked nearer the apex, 12; apical pinna divided or forked more than once, 19; fronds having one lateral pinna forked, 35; fronds having two lateral pinnæ forked, 5; fronds having three lateral pinnæ forked, 2; fronds having four lateral pinnæ forked, 1. It is evident from the above facts that a careful search will reward the diligent searcher with further varieties; and the experience of English fern-growers has proved that when once a natural sport has been obtained it produces spores from which an unending series of forms can be cultivated. Mr. Field, a veteran collector and observer of New Zealand ferns, has written in the Transactions on the variations in the manner of growth of several species of ferns in the North Island, * Field, H. C: “On the Growth of Ferns; and on a New Fern now first reported.” Trans. N.Z. Inst., xxvii., 446, 450. and points out that what is taken as a species may vary much in general habit in different localities. Curiously enough, Mr. Field, although he has had more than half a century in the New Zealand bush in the North

Island, has stated * Journ. of Botany, xxi., 1883, p. 140. that he has never seen any variation such as I have recorded above. Although my modest experience of New Zealand ferns in the bush only dates back to 1877, I have had the good fortune to come across abnormal varieties in many genera and of many species. I am referring now to abnormal varieties in the pinnæ, and not to such varieties as are recognised by the species-maker as a rule. There is, however, one well-marked variety, discovered by me in the Whanakino Creek, in the ranges at the back of the Hawke's Bay Provincial District, which has received a name and description from the late Rev. W. Colenso. It is a form of Polypodium pennigerum var. hamiltonianum, Col., which has remained constant under cultivation for years. A variety of Lomaria, described by the late T. H. Potts as Lomaria duplicata, †Potts, T. H.: “Notes on a Lomaria collected in the Malvern District (L. duplicata).” Trans. N.Z. Inst., ix., 491; 1876. is only a form of Lomaria procera in which the stipe is persistently divided. A form of a rather uncommon fern, Asplenium umbrosum, was described by the late Thomas Kirk, ‡T. Kirk: “On a Remarkable Variety of Aspl. umbrosum, J. Sm.” Trans. N.Z. Inst., xxiii., 424—425; 1890. from Takaka, Nelson, where it was found by Mr. J. McKenna Campbell, as var. tenuifolium. It is mentioned that the plant has a pleasant fragrance, a peculiarity which it shares with a Doodia and with Polypodium pustulatum in New Zealand. There are many species in various parts of the world which are fragrant, and retain their odour for a long time in the dried state. One species, Polypodium phymatodes, is used largely in the Polynesian Islands for scenting the cocoanut-oil used for the human body. The odour of all these ferns is apparently due to oil-glands in the substance of the fronds. In England many of the Lastreas are scented. It is not often that sports are observed in tree-ferns, but Mr. H. Matthews, the Government Forester, informs me that some years ago he sent to Kew Gardens a fine specimen of Dicksonia squarrosa which had all the pinnæ forked or crested. This plant came from the Catlin's River district. Other species which I have found in a crested condition in the North Island are: Adiantum cunninghamii, Hk. Of this I obtained two crested plants on the limestone rocks at the gorge of the river at Puketapu. These plants were grown in Mr. H. S. Tiffen's fernery, and when I last saw them were quite constant.

Cheilanthes tenuifolia or sieberi: This is an extremely variable fern in the neighbourhood of Petane, Hawke's Bay, and I have found many divided and otherwise irregular fronds. At one time or another I have found abnormal fronds of nearly all the common Lomarias, especially L. procera, L. discolor, and L. alpina. In Asplenium I have gathered A. trichomanes beautifully crested on the rocks near Petane, and near Waipawa, in a small patch of bush, a very curious form of A. flabellifolium. Mr. A. C. Purdie had a well-crested form of A. falcatum, originally found on Quarantine Island, near Port Chalmers, and I have seen other plants in cultivation in Dunedin. I have not gathered many abnormal fronds of Aspidium, though this is a group in which many sports may be looked for. I have specimens of A. aculeatum with divided fronds, and have seen a very remarkable form said to have been obtained on Saddle Hill, in the Taieri district of Otago, which carried young plants on the under-surface of every frond about 6 in. from the tip, the fronds being about 3 ft. long. On the Waitati Saddle I have seen plants of this fern which showed a bend or weakness in the otherwise normal frond at just about the same position on the frond. The plant was cultivated for years by the late Mr. A. C. Purdie, but has, I am afraid, passed out of existence. * Since writing the above note I have seen other plants of this variety. In the frond now before me, from a small plant with fronds averaging about 12 in., the young bulbils are aggregated in a bunch 1 m. from the apex of the frond. Some of the bulbils have aborted, but two have developed fronds ¾ in. in length, and two of these carry fully developed sporangia on every pinnule. The frond only developes these bulbils in the autumn. The main bunch of bulbils is at the base of a pinna on the right side of the main rhachis, but each of the two lower pinnæ on the other side have a less developed bulbil at a point where they form the rhachis. One of the most striking forms that I have seen was brought to me by Mr. C. W. Adams from the Catlin's River Bush. It was a large mass of Polypodium billardieri much crested. I had this plant in cultivation for some years, but one very severe winter it died out. I have seen a similar form in a nurseryman's collection in Christchurch. Polypodium tenellum also sports into crested forms, one of which I gathered at Tongoio. In the neighbourhood of Dunedin the Leptopteris hymeno-phylloides is usually much more lanceolate in form of frond than in the North, and appears to be affected by some fungoid(?) disease which thickens the pinnules irregularly, making them crisp and brittle and markedly dissimilar to the other pinnules, quite spoiling the feathery appearance of the frond.

In view of the number of crested, divided, and otherwise abnormal ferns which I have seen, it was somewhat of a surprise to me to find that Mr. Field, in a note in the “Journal of Botany,” * Field, H. C.: “Variation in New Zealand Ferns.” “Journal of Botany,” xxi., 140, 141; 1883. says, “I have never met with a crested New Zealand fern, and only once or twice with a depauperate one, while variations in colour are common.” I think if special search were made for crested forms it is quite possible that some of great interest and beauty may be found, and if cultivated with skill there are endless possibilities in the future, as it is now a well-established fact that crested ferns rarely revert to their normal state when raised from spores, although occasionally a further distinct form will present itself. For nearly forty years a small group of English fern-growers have been working at the task of raising plants from spores of plants found wild under natural conditions, and a large number of facts have been gathered which wait a master hand for deductions. Although so much was done by Darwin in his researches on animals and plants under domestication, in which he brings together a vast host of facts derived from the vegetable and animal kingdom, the record anent ferns, which in some respects present unique powers of variation, is summed up in a solitary short remark about the power of spores taken from abnormal fronds to reproduce the abnormal character. Those who wish to take up some branch of botanical study will find a wealth of material at hand, either in a scientific study of the behaviour of the prothalli under various conditions in the living state, or by the microscopical investigation of the anatomy of the leaf-stalk and the dispositions of the stelæ. This latter character has been investigated lately in the hope of finding more absolute characters for the discrimination of genera. Much interesting detail will also be found in the structure of the filmy ferns. The quest for naturally crested or divided ferns for cultivation will add to the enjoyment of many a walk or scramble in the bush, and careful selection of plants raised from natural sports will amply reward the care and trouble required to produce good results in this as in everything else. Search should also be made for examples of apospory. I have not yet seen an example in New Zealand ferns, but in an Annual Report of the Colonial Museum there is an entry which may be a record of this: “1754.—Feb. 24, 1887.—Fern, Asplenium obtusatum, supposed to be a new variety; proliferous on the upper surface. Sent by Miss Marchant.”

[Note.—In the following list “Trans” means the “Transactions of the New Zealand Institute.”] Author. Title. Name, &c, of Publication. Armstrong, J. B. On a Natural Arrangement of the New Zealand Ferns Trans. xiii. 360; 1880. Baker, J.G., F.R.S. A Summary of New Ferns which have been discovered or described since 1874 Ann. of Botany, 181; 1891. Buchanan, John, F.L.S. On the Root-stock of Maiattia fraxvnea Journ. Linn. Soc. xvi. 2. Trans. ix. 527–529; 1876 On a Remarkable Branching Specimen of Hemitelia smithii Trans. xix. 217, pl. xii. and xiii.; 1886. On the Flowers, Plants, and Ferns of the Chatham Islands Trans. vii. 333; 1874. Cheeseman, T. F., F.L.S. Description of a New Species of Hymenophyllum " viii. 330; 1875. Description of a New Species of Polypodium " x. 356; 1877. Notice of the Discovery of Asplenium japonicum, a Fern new to the New Zealand Flora " xxii. 448; 1889. A Description of some New Ferns lately discovered in New Zealand The Tasmanian Journal, i. 375; 1842. Colenso, Rev. W., F.R.S. Description of Two New Zealand Ferns believed to be new to Science Trans. xi. 429; 1878. The Ferns of Scinde Island " xiii. 370; 1880. On some New and Undescribed New Zealand Ferns " xiii. 376; 1880. A Description of Four New Ferns from our New Zealand Forests " xv. 304; 1882. On a Large Number of Ferns noticed in a Small Area in the New Zealand Forests, in the Seventy-mile Bush, between Norsewood and Dannevirke, in the Province of Hawke's Bay " xv. 311; 1882. A few Observations on the Treeferns of New Zealand, with Particular Reference to their Peculiar Epiphytes, their Habits, and their Mode of Growth " xix. 252; 1886. On Newly Discovered and Imperfectly Known Ferns of New Zealand, with Critical Observations " xx. 188; 1887. Description of Three Newly Discovered New Zealand Ferns " xxiv. 394; 1891. A Description of a few Lately Discovered Rare Indigenous Ferns " xxv. 319; 1892.

Colenso, Rev. W., F.R.S. A Description of Two New Ferns and One New Lycopodium lately detected in our New Zealand Forests Trans. xxvii. 399; 1894. A Description of Two New Ferns, a New Lycopodium, and a New Moss, &c. " xxviii. 615; 1895. Description of Three New Ferns, believed to be undescribed, discovered more than Fifty Years ago in the Northern District of New Zealand " xxviii. 618; 1895. A Description of some New Indigenous New Zealand Forest Ferns " xxix. 414; 1896. A Description of some Newly Discovered New Zealand Ferns " xxxi. 263; 1898. Enys, John On Recent Changes in the Nomenclature of New Zealand Ferns " iii. 213; 1870. On the Occurrence of Botiy-chium lunaiia, Swb. (Moon-wort), in New Zealand " xvi. 363; 1883. Field, H. C. Notes on New Zealand Ferns N.Z. Journ. of Sc. i. 128. Variation in New Zealand Ferns Journ. of Botany, xxi. 140; 1883. On the Growth of Ferns; and on a New Fern now first reported Trans. xxvii. 446; 1894. On Curious Forms of New Zealand Ferns " xxx. 434; 1897. Notes on Hybrid Ferns " xxxv.; 1902. Hamilton, A. Notes on some New Zealand Ferns " xxii. 493; 1889. Notes on a Branched Specimen of a Tree-fern, Hemitelia smithii " xxviii. 622; 1895. Hector, Sir James Corrected List of New Zealand Ferns " iii. (at end of vol.); 1871. Kingsley, R. I. On a Remarkable Variety of Lomaiia lanceolata " xxv. 306; 1892. Kirk, Thos., F.L.S. Notice of a Remarkable Arborescent Fern on Ngongotaha " v. 347; 1872. On the Specific Characters of Dicksonia antarctica, Br., and D. lanata, Col. " v. 345; 1872. On the New Zealand Forms of Cheilanthes " vi. 247; 1873. On Nephrodium pentangularum Proc. N.Z. Inst. x. 531; 1877. On Hymenophyllum armstrongi Proc. N.Z. Inst. x. 532; 1877. Description of a New Species of Hymenophyllum Trans. x. 394; 1877. On Lindsaya viridis, Col. " x. 396; 1877.

Kirk, Thos., F.L.S. On Nephrodium decompositum, Br., and N. glabellum, A. Cunn. Trans. x. 398; 1877. On Hymenophyllum villosum, Col. " x. 395; 1877. Description of a New Species of Hymenophyllum " xi. 457, pl. xix.; 1878. On the Ferns and Fern Allies of Stewart Island " xvii. 225; 1884. On a Remarkable Variety of Asplenium umbrosum, J. Sm. " xxiii. 424; 1890 Potts, T. H. Habits of Filices observed about the Malvern Hills, near the Gorge of the Rakaia River, Canterbury, New Zealand Journ. Linn. Soc. (Bot.) xv. 423; 1876. Notes on Ferns Trans. x. 358; 1877. Notes on a Lomaria collected in the Malvern District " ix. 491; 1876. Ralph, T. S. On the Arborescent Ferns of New Zealand Proc. Linn. Soc. iii. 163. Thomson, P. Notes on Rare Ferns Proc. N.Z. Inst. vii. 540; 1874.