PLANTS OF THE DUNEDIN DISTRICT.

Otago Daily Times, Issue 19202, 19 June 1924, Page 11

PLANTS OF THE DUNEDIN DISTRICT.

XII.—THE FERNS. Written for.tho Otago Daily Times. By Wm. Mahtjn, B.Sc. The ferns and fornJiko plants of Dunedin number seventy-live; but the mosses, numbering several hundreds, have hitherto neither been listed nor counted. Ferns, masses, lichens, liverwort.-, and algae are more lowly in organisation than the flowering plan)H we have boon considering and are propagated by spores in place of seed. Our largest group of ferns is that which comprises the filmy ferns, locally represented by eighteen of Mow Zealand’s twenty-seven species. These beautifully dedicate plants have leaves or fronds but a single cell thick, and can thrive in most cases only where the air is nearly saturated with moisture, as in the interior of the densest forest. Some, it is true, are rarely found in bush, and on Ra.ngiloto one—the kidney fern—actually grows on rocks exposed to (ho fiercest summer sun. _ All absorb moisture directly from the air by moans of Ibeir fronds, which, of course, higher plants usually do by means of their roots. A few are, as a. rule, confined to ihe stems of tree ferns, others to the limbs of trees or to rocks or to I he forest floor, while one, Hyrncnophylluin Malingii, is wholly confined to the trunks of the native cedar and totara, but very rarely the latter. Of the first group the commonest is the bristle-fern (Trichomanes venosum), a small species with rihbon-likc loaves and leaf segments. On the base of almost any tree tern growing in damp bush or near tho bank of a stream, this fern is almost sure to bo found. Another small species with broader fronds (Jtfyinenophyllum rariun) is much more common than its name suggests, and grows as a rule higher up the trunk of tho tree fern than the hnstlo-fcrn. H. flabellatum _ is almost equally common, but grows just as frequently on other trees us on the tree fern. Its name, when translated, means the fanshaped, thin-leaved fern, which is quite an appropriate title. Tho largest of tho filmy ferns are K.sangiiinolcntnni. IT. dilitetnm, 11. Demissnm, H. Pulehoirimum. and H. bivalve. Locally the fronds seldom reach a foot _ in length or half that breadth, though in Westland fronds of the same species may on occasion he several feet long. The first-named thrives its descriptive distinguishing name from the circumstance that fronds pressed between the leaves of a -book when dry slain (he paper red or rust-coloured. 1 he second species is now confined (o dense, bush at high levels, as on Mount Cargill and Signal Hill, duel to a fow bush remnants near Pukehiki. on the peninsula* 11. demissnm is one of the. very commonest, and frequently carpets large, areas of_ tho forest floor, which the next one never does. H. pulcherrinnun grows in single tufts, and has a broad wing on cither side of the “stem cf its leaf.’’ These will bo found either on the ground or more usually on a tree trunk near the base. H. bivalve is a. very common draping cf the limbs of trees. A very much crimped species, with a crinkly wing on the leaf stalk, has been reported from Flagstaff and from Mount Cargill, hut I have not met anyone who can authenticate this statement. I refer to H. australe. A very similar species, if, indeed, it is not in reality a form of tho same plant known as FT. atrovirens, has for some time been known only from a. single sniot on Morrison's Creek. buShave noted it latch- at Powder Creek,'’at Whare Flat, and also on ihe hank of a stream flowing through the bush at Wood side. Curiously enough., onr rarest fern —Colenso’s bristle-fern (Trichomanes Colensoi)—grows at. identically the same stmt at Morrison’s Creek as 11. atrovirens, while, close to it at Wondsido I found the Tunbridge fern (IT. -tunbridgensel, _ so named after its English habitat, for it is a worldranging species. On. Flagstaff and in Ibe valley of Ross Creek. IT.' neltetum, which is probably a form of tho Tunbridge fern, is still occasionally seen. H. Snabrum is now very scarce, and likewise H. ferrugincum, formerly known from Pino Hill and from Sawyers’ Bay. but last seen in 1895. On the other hand, H. multificlnm is very common both in the upper bush and in rock crevices on Flagstaff and Maungatua, where it ranges right fo tho summit. Our last, species, H. villesum, thougli quite common, has apparently been overlooked till this year, when the Rev. Dr Holloway, (he foremost, student of this group, found it on Mount Cargill, Coming next to the tree-ferns, of which we have five kinds, the commonest by far are the slender-stemmed harsh-leafod Dicksonia squarrosa and the thick-.stemmed softleaved Ilemitclia. The silver tree-fern is common on the northern side of (he harbour, and formerly was equally so on Pino Hill and on the Peninsula. Idle fourth spccirs ill ways has n prostrate stern and might well he passed over as belonging to some other typo, hut. on Flagstaff, in particular, and also on mest hillsides of the district with a southerly aspect (other than Chain Hills), it. is common enough. Because of its shade-lovino- propensities it is known as Alsophila Colensoi. The silver tree-fern Cyathea dealbata. still common enough on iho hills round iho Jiarbour in Leith Valley, cannot be mistaken from the silver colour of the lower surface of its fronds, The fifth tree-fern appeal's to have been known locally only from Fraser s Gully, but I recently noted it at West Taieri in the patch of bush which extends out. on to the Taieri Plain. By name it is Dieksonia fibrosa, so called in reference to its stc.iit, fibrous trunk. It may be distinguished from tho somewhat similar HonutoHa by the harshness of its loaf texture. One 'of the most beautiful of our ferns (Davallia novae-Zealandite)— the local representative of tho well-known hare e-foot fern —is well distributed over the district though it is never abundant. For some strange reason if has occasionally been described as a very rare fern locally, but such was never a fact. T have seen it on the Peninsula Chain Hills’ (in the bush near the mouth of the tunnel), Leith Valley, Morrison's Crook. NioholVCreek, and m numerous localities on Mount Cargill, Hi mat Hill and northern side of the harbour generally. as well as at West: Taieri. The maiden hair fern (Adiantum affine) L perhaps less common now than formerly, but on Mount Charles, on the cliffs near Blueskin Bay, and on the rock faces near the Brighton creamery, it may yet be seen in plenty. . , , .. Tho genus Lomana or Bleehnum, as it is now generally recognised, is locally represented bv eight siir-nios. and may lie recognised by the fact that it produces (wo kinds of frond—the foliage and the sporehearing fronds. Much the commonest form abundant on the open hillsides or in light hush aa at Maungatua is (he hard-fern (Bleehnum Capense). 'J no more correct epietiiei, for those ferns would he bnrdyferns,” as many can be transplanted with ease and grown successfully. By the sides of streams especially in hush, B. lancedatum and B. fluvial Ho are much the commonest hard ferns,-the first with pointed j oa f anti flit 1 l&ttor with round leaf segments. A species very common at Wha're°ria.t awl not uncommon in Leith Valley and Fraser’s Gully is B. vulcanicum, a fern very like B. Capense. but distinguished by its more jiointcd fronds and hv the lowest, pair of leaf-segments which point downwards. A very largo erect-grow-ing species, commonest at (he higher levels in bush, is B. discolor, which is indeed very like a giant form of B. cancoolaUnn. The smallest, species is B, ponnama.rimnu, or what used to bo called by the more euphonious name of Lc.maria alpina. This is commonest on grassy hillsides, though growing at times on the floor of the forest. Another species confined to very damp forest (15. Patersoni) has very largo, deeply divided dark green fronds, and may be seep in any suitable locality—e.g.. NTeboll's Creek, near (be gorge, a couple of hundred yards from the Leith Valley road. Another B. durum species once reported from Sea View by Mr A. Purdie has not been seen in the" district for many years, but a smaller and more prostrate species, B. Banksii, which is confined to coastal banks, is very common near Bruce’s Rocks, and occurs at Anderson’s Bay on the north side. Our next genus with an equal number of ronrcsent.ativo.s is Aspleniwn. the name applied to all the Hploenworts. In every piece, of hush in New Zealand ihe hen-aiul-chiokeu fern (A. Indbifernm) may be confidently looked for. while a drooping species ijbnost confined io limbs of trees (A. flaccidum) is frequently little less common. Wh ere Ihe ground is drier and light can penetrate (he hush A, Hookoriaimm, (ho smallest species other than the next, may lie expected. H is; very common a.t Mount Charles, in Mr Barling’s Rush at; Macandrew’s Bay, on Saddle Hill, and the Chain Hills, as well as at Whare Flat, ami Ma.nngaliiil A flabolllfolinm is a trailing plant with thread-like stems and numerous pairs of leaflets. FToqnently a hud develops at, tho tip of the frond from which a, now plant arises. At Powder Creek a remarkable examnlo with this second plant producing still other plants al; the tips of its own fronds, and these in turn repeating tho process, was recently discovered, ;

On - Gout Island, near Porlobello, A. adiantoides may still !>e found, but this forn docs not grow anywhere else in tho district'. On all coastal rock faces a very thick leafed species, A. obfuaatum, is common—as al Black Head or Forhury Head or Lawyer’s Head —while in loss exposed situations along the const a similar plant with divided' leaf segments—evidently a form of A. Jyynllii—is equally abundant. The shining spleen wort, A. Jueidum, glows on Pudding’ Island and on Goat Island in the harbour, together with forms of A. Lyalin. At Whare Fiat A. Riehardi is not altogether uncommon. All of these spleenworts may be recognised al once when in spore, for the spore-capsules arc packed info slits on (ho back of tho frond placed at an approximate angle cf 4Sdeg to the midrib. Three shield-ferns are common. Tho first is a tall growing plant with very shaggy leaf stalks am! midribs. Occasionally it forms a. miniature trunk. The old name is Aspidium aouleatum, the new olio Polyslichum vestitum. The second plant has a leaf of darkest green —almost black in fact—and like ail shield ferns has its spare capsules clustered under little round sbiods or umbrellas on the back of tho frond This is P. Riehardi. A. adiantiforme is a < limbing species almost always found on the. trunk of a free fern and not easily confused with any other. Specimens may be noted in Morrison's Creek and at jPortobello and at Macandrews. Similar ferns will) kidney-shaped shield-, formerly known by the name iVephrodium, are represented by at losat three, if nob four species. One species, with rough, hairy stems, is on that account known aa Oryopteris hispida.. another with smooth Jeaf stalks is If. glabella ; a. third, not seen lor years and restricted to New Zealand, has a velvety stem, and i s called D. vchitina. If, decomposite is said in the catalogue to be common in bush, but 1 cannot say it* is really common. Brackens have three species—(he common bracken, (he hush-bracken. Histroptcris in-' cica, abundant on Mount Cargill and most bush margins elsewhere, and the pig-fern or iace-fern, Pl-eris seabe.ruJa, a graceful plant of open spaces in damp localities. On the slope's of Flagstaff and elsewhere two very similar deciduous ferns abound—llypolcpis millefolium ami 11. though the latter is more common on ibd Pine Hill-Mount Cargill ridge. A third, llvpolepis (1:1. distans) formerly grew at the bead of Tomahawk Lagoon, but was thought to have vanished from (he district till. Air S, Furla.nd last year showed mo specimens from the (silver Peaks. I also found it this year at Wooclside. On Harbour Cone and in the bush near the Gardens abounds a dark-leafed fern, Pelloea. rotiindifolia, with’ numerous; rounded leaflets • al intervals along the midrib. While not altogether common elsewhere, it is quite;: frequently seen, always where the soil is dry. In collections I have seen specimens from Dunedin with more pointed leaflet* quite crrooonsly labelled P. falcata, which does not grow south of Nelson. A very interesting fern, living only in the very driest of situations, still grows on the cliffs o the south side of Anderson’s Bay. Tho Hon. G. Al. Thomson, in his Naturalists’ , Calendar, refers io it as a tilin'- of (he past, hut a fow plants still persist in this its only known local habitat. Six polvpoflies, two todcas, an umbrella fern, a moonwort, and tho adder’s tongue fern complete the list. At high levels: on rocks and trees tho tiny Pctypodium australe {ol d name), and the cohaceoys P. granimitidis abound, as does the common' 1 creeping polypody P. diversifollum in the bush at lower levels. Another tall species, growing only in stream beds in the hush—o.g,, on Mount Charles—is now becoming comparatively rare. Tills is P. penninerum. ‘ Another kind, 1 resembling some form of bracken frequents the margins and open spaces of bush—o.g.. Mount Cargill, while a round or strap-leafed species of very thick texture is particularly common on certain Iroe trunks. It is veryfond of broadioaf and macrocarpa stems and rock faces and owns Uic descriptive title of Gydopliorus serpens. About 1878 JMr Smith, while engaged on the survey of the water race at ''hare Flat, chanced on a clump of umbrella fern, Gleieheiiia Cunmnghamii, which (o this day is the onlv clump in the whole Dunedin district. It now occupies lass than a square yard and is very sickly in appearance. In tho early days a cl urn in Nichol’s Creek and another tn Morrison’s Creek were also known, bub these have been destroyed by visitors to these delightful spots. The tiny adder’s tongue, Ophioglossum vulgalutn, though still common on Flagstaff and Maungatua, is hard to locate. It grows out in the open grassland. The moon Avert (Bolrycbiurn temal um) I have not seen lately, _ but it used to bo common. By many it was known as the carrot tern because of a fancied resemblance seen in (he foliage. It was last seen in 1915 near Mr I Bon Rudd’s road on Mount Flagstaff. Hie water fern Azolla rubra is abundant on Tomahawk Lagoon, large areas of which, are on occasion obscured by its red fronds. It differs from true ferns in producing two kinds of spores. Club mosses or lycopods are represented by at least five species. Tho long trailing species growing from tho branches of trees in the bush is Lycopodium Billardieri. A very similar erect species, growing on rocks on Mihiwaka and Maun gate a, is known as L. vatium, while on Flagstaff’ and Swampy Hill. etc.. L. fastigiatum, L. scariosnm, and the' climbing L. vohibilo are exceedingly abundant. Our last plant is " one which' like the tuatara, appears to be a living fossil without relatives in the world. It grows on the trunks of tree ferns, where it ,rnay easily be identified by its unbranched I steins up to a foot in length and thick, triangular pointed leaves. This plant has recently been minutely studied and described by Dr Holloway, who is our foremost authority on all me plants mentioned' in this chapter. Coxn.rsiox, In bringing this series to a close. I desiro to acknowledge with gratitude numerous messages of appreciation, information, and criticism. I am grateful to Dr L. Cockayne, F.R.S., for' calling my attention to an error in Chapter I. 1 quoted ’‘Contributions to New Zealand Botany.” by Dr Lauder Lindsay, F.L.S.. F.R.S.E., who says (p. 8): “The earliest botanical explorers in Otago appear to have been Sir Joseph, Banks and Dr Solander. . . . Their collect inn seems to have been mainly of West Coast species.’’ Dr Cockayne points end. however, and Captain Cook in his log slates, (bar they did not land owing to foul weather. By an oversight the name of Mr Henry Matthews was given as Mr Geo. Matthews, while those of Messrs R. M. Laing and. J. Crosby Smith, who worked up the local seaweeds, were unintentionally omitted. Mr W. J. Williams has also contributed greatly to our knowledge of local plant distribution. Mr J. S. Thomson reports OJearia. nummularfolia and Veronic a salicormioidea as still to be been on Maungatua, while Mr A. W. Bathgate reports a plant, of Teporidiuin from Saddle Hill While I have not mentioned every plant in the district, tho omissions are not numerous, and I trust that- these notes may prove userid in days to come. The previous articles were published ini our i ucs of March 5. March 15, March 24, April 2. April 5, April 22, April 30, May 7 X , May 12, May 26, June 10, and June 13.