Art. XXV.—On the Ferns and Fern Allies of Stewart Island.
[Read before the Southland Institute, 13th January, 1885.]
From the short sketch of the chief physical and climatal characteristics of Stewart Island given in a previous paper,** it will be seen that the conditions are highly favourable to the development of a luxuriant fern-flora, and such we accordingly find, whether considered with regard to the rich free growth of the individuals composing a species, or to the actual number of species found on the island. Swamp, forest and open land—sea-level, hillside and mountain-peak—alike exhibit characteristic forms, and include species whose occurrence in such high latitudes could not have been anticipated.
The chief points of general interest presented by the fern-flora of Stewart Island are—
1. The great abundance and luxuriance of arborescent ferns, which occur in nearly all situations at low levels, and exhibit an extension of the geographical range usually given in our text-books (45.50) to 47.20 S.
2. The large, unusually large, proportion of Hymenophyllaceæ. Of the twenty-seven species of “filmy-ferns” generally recognized by botanists in New Zealand, no fewer than twenty occur in Stewart Island. They form only one-fifth of the entire fern-flora of the colony; but rise to one-third on Stewart Island.
[Footnote] * See above, Art. xxiv.
3. The excessive amount of variation exhibited by certain species, as Asplenium bulbiferum, A. obtusatum, etc., which is much greater than in any other part of New Zealand.
4. The occurrence of certain species of a northern type, as Lindsæa linearis, Trichomanes lyallii.
I purpose drawing attention to these features at greater length in the notes appended to the following enumeration of the ferns and allied plants observed on the island.
Gleichenia circinata, Swartz. Not uncommon on the margins of swampy forests.
G. dicarpa, Br. Abundant in woods. Stipes slender, wiry, sometimes 18″ high, with from six to nine series of branches.
β. alpina. Common in open moory places 1′–4″ high, often reduced to a single pair of branches. Passes gradually into the typical form. Ascends to 3,000 feet.
G. cunninghamii, Heward. Woods and sheltered places by streams; not common; and never exhibiting the extreme luxuriance of northern specimens.
Cyathea medullaris, Swartz. Port William and Halfmoon Bay; rare and local. Does not attain large dimensions. The occurrence of this species so far south is quite unexpected.
Hemitelia smithii, Hook. In forests throughout the island; sometimes attaining the height of 25′. Two principal forms may be distinguished: a. Segments broad, teeth acute, few. b. Segments longer, with obtuse teeth; much more elegant than a. The young fronds and the pith of the stem were formerly used by the Maoris as food, and are still collected for cattle. Ascends to nearly 1,000 feet on Ruggedy.
Alsophila colensoi, Hook. f. Two specimens observed in a deep wooded gully on Mount Anglem. Alt. 1,500 feet.
Dicksonia squarrosa, Swartz. Throughout the island, abundant. Often forming groves covering many acres under large trees. Branched specimens are occasionally seen, and in many places the stem is completely hidden by crowns of short fronds, given off direct from the stem in such a way as at first sight to suggest the idea of the stem being covered with an epiphytal growth of young plants. It is, however, easy to prove their organic connection with the stem. One of the most characteristic plants of the island, occurring in all lowland situations except open swamps.
Hymenophyllum armstrongii, T. Kirk. Rare. At the base of shrubs, etc., Peaks of Ruggedy.
H. tunbridgense, Sm. In forests and rocky places. Common.
H. unilaterale, Willd. Rare and local. Steep banks of a stream near head of Paterson's Inlet.
H. minimum, A. Rich. On rocks, trunks of trees, etc., near the sea, not unfrequent. Fronds with from two to six pairs of lobes.
H. bivalve, Swartz. Common on mossy banks, in damp situations, and in forests. a. Fronds rigid, decurved. b. Fronds slender, flat, sometimes nearly 1′ in length.
H. multifidum, Swartz. Common throughout the island, ascends to fully 2,000 feet.
H. rarum, Br. Remarkably local. Ulva. Port William.
H. pulcherrimum, Col. Observed only at the Archdeacon's Cove, Paterson's Inlet. Fine pendulous fronds measured nearly thirty inches in length.
H. dilatatum, Swartz. Common throughout the island at low levels.
H. javanicum, Spr. A solitary specimen of this species was collected on Ulva.
H. polyanthos, Sw., var. sanguinolentum. Most abundant, and exhibiting a wide range of variation in the shape of the fronds, caused by the unequal development of the pinnæ. Occasionally the lateral pinnæ are less than half an inch in length, while the apical portion of the frond is greatly elongated, sometimes being over a foot in length. Again, the lateral pinnæ alone are elongated so as to form a broadly flabellate frond. A diminutive form with fronds less than half an inch in length is found on the mountains.
H. villosum, Col. Mount Anglem, 3,000 feet.
H. demissum, Sw. Abundant below 1,800 feet.
H. flabellatum, Br. Epiphytic, not uncommon, ascends to 2,000 feet on Mount Anglem.
H. rufescens, T. Kirk. Rakiahua, Messrs. Hamilton and Goyen!
H. æruginosum, Carm. Abundant on trunks of tree-ferns. Extremely luxuriant at Port William.
Trichomanes reniforme, Forst. Paterson's Inlet and Halfmoon Bay. Restricted to a few square yards above high water-mark in each locality. For my knowledge of these habitats I am indebted to Mr. Walker.
T. lyallii, Hook. On inclined trunks of Metrosideros lucida, Mount Anglem, 1,500 to 2,200 feet. I was much surprised at the discovery of this species on Stewart Island.
T. strictum, Menzies. Extremely rare and local. Ulva. Discovered by Miss Traill.
T. venosum, Br. On stems of tree-ferns, etc. Port William, Ulva, and other localities, not uncommon.
Lindsæa, linearis, Swartz. Head of Paterson's Inlet, Mason Bay.
Adicantum affine, Willd. Port William and Halfmoon Bay. Rare
Hypolepis tenuifolia, Bernh. Not uncommon on the margins of forest, etc.
Pteris aquilina, L., var. esculenta. Common.
P. incisa, Thunb. Abundant: in open places forming extensive patches.
P. scaberula, Sw. Common.
Lomaria capense, Willd. Abundant in woods, etc. In deep gullies the sterile fronds are sometimes from eight to ten feet in length and two feet eight inches in breadth.
var.minor. Frequent in open places, and on mountains.
Lomaria fluviatilis, Spr. Moist places in woods, etc., common.
L. vulcanica, Blume. Rocky places in woods; frequent. The young fronds are of a delicate pale red colour.
L. patersonii, Br. Local. Island of Ulva. Near Ruggedy.
L. lanceolata, Spr. Abundant in woods and on the banks of streams, etc.
L. discolor, Willd. Abundant in forests. Stems erect, 1–2 feet high.
L. alpina, Br. In open swamps and on mountains; common.
L. dura, Moore. A very handsome fern, frequently forming a dense fringe above high water-mark; but never found inland. Fronds 1–2½ feet long: pinnæ frequently dense and overlapping.
L. banksii, Hook. Littoral; rare. Paterson's Inlet, etc.
Asplenium obtusatum, Forst.
α. Pinnæ, thick, fleshy, entire or serrate, obtuse. Fronds one inch to two feet long. Common near the sea.
β. scleropium. More or less finely serrate, the teeth varying in length in different specimens; sometimes extending nearly to the midrib of the pinna. Near the sea. Forming large patches on Herekopere Island.
Note.—Fronds with the pinna entire are frequently found on the same plant, with deeply-serrated fronds.
γ. lyallii. Fronds with pinnæ pinnate or pinnatifid at the base. Mason Bay.
δ pseudo-falcatum. Fronds greatly elongated, 3 feet long or more, drooping, coriaceous; pinnæ broad at the base, suddenly acuminate, coarsely toothed. Mason Bay; in forests.
A. falcatum, Forst. Common in forests, epiphytal. Forming extensive patches on open land. Herekopere Island.
A. bulbiferum, Forst.
α. vera. Common.
β. laxa. Common in deep gullies.
γ. tripinnatum. In forests. Less common than the preceding.
δ. integra. Pinnæ nearly entire—or with shallow lobes or teeth. Resembles some states of flaccidum; but bulbils are always developed. Island of Ulva.
ε. pseudo-lucidum. Fronds oblong-lanceolate, stipes short, pinnæ nearly entire or deeply toothed, lobed or almost pinnatifid; coriaceous; bulbils of large size. Island of Ulva.
decomposita. Fronds 1–3 feet long, drooping, coriaceous, 3–4 times pinnate, segments narrow-linear, acute, sori marginal. A beautiful variety; the most highly divided form of the species. Island of Ulva.
A. flaccidum, Forst.
α. In forests.
β. In forests and on rocks.
γ. Cliffs by the sea.
Aspidium aculeatum, Swartz., var. vestitum. Common. A form approaching A. angulare, Willd., occurs on Ulva. Another scarcely to be distinguished from the European typical form is found at the Old Neck. The caudex is frequently erect, and much branched. The scales on the rhachis vary greatly in size and density. The non-indusiate form was not observed on the island.
A. capense, Willd. Common in forests, etc.
Nephrodium hispidum, Hook. In forests. Common.
Polypodium rugulosum, Lab. Common.
P. grammitidis, Swartz. Common on trees and rocks.
P. serpens, Forst. Abundant on trees and rocks.
P. pustulatum, Forst., vera. P. billardieri, Handbook N.Z. Flora. On rocks and trees, abundant, but always less luxuriant than in the north.
P. australe, Mett. Common. Ascends to 2,000 feet.
P. crassium, MS. A singular little plant usually confused with P. australe, var. alpina, but differing in the elongated flexuous or twisted rhizomes; 1″–3″ long; fronds narrowed into a distinct stipes, broadly ovate, coriaceous, unisoriate; sorus attached to the centre of the frond. The fronds are arranged in three series along the rhizome, and are never tufted. Bare rocks on the highest peaks of Mount Anglem; 3,000 feet.
Todea hymenophylloides, Presl. In forests, local. The Old Neck, etc., etc.
T. superba, Col. Local, but not unfrequent. In deep woods; head of Paterson's Inlet, Ruggedy, the Archdeacon's Cove, etc.
Schizæa fistulosa, Sw., var. australis. S. australis, Gaud. Forming small dense tufts in swamps. Head of Paterson's Inlet, etc. Fronds 1″–2″ high. In a few places on the terraces larger specimens were found showing a direct transition to the typical form.
Lycopodium selago, L. Port Pegasus, Mr. Petrie!
L. varium, Br.
L. ramulosum, T. Kirk. On open peaty land and in swampy woods. Stems excessively branched and prostrate, densely matted. Head of Paterson's Inlet.
L. clavatum, var. magellanicum. Common; ascends to 3,000 feet.
L. scariosum, Br. Low sand ranges and terraces between Paterson's Inlet and Mason Bay. Island of Ulva.
L. volubile, Swartz. In forests; not uncommon.
Tmesipteris tannensis, Sw. On rocks and trees, frequent.
Azolla rubra, Br. Ruapuke Island. A. W. Traill!
It is not easy to account for the apparent absence of several species, such as Dicksonia antarctica, Hymenophyllum scabrum, Aspidium richardii, Nephrodium glabellum, Polypodium pennigerum, and especially Asplenium hookerianum, and A. colensoi. In all probability several of these will be discovered before long.
This paper may be fittingly concluded with brief descriptions of two natural “ferneries” on Stewart Island.
The first is a narrow gully, or deep ravine, in the forest on the island of Ulva. At the head of the ravine is a small cascade, which gives rise to the stream flowing through the gully. The whole is shut in by large trees so that direct sunlight is excluded, and the sides of the gully, at first steep, are gently rounded-off in the upper portions. The conditions are eminently favourable for luxuriant fern-growth.
At first the visitor's attention is arrested by large masses of tree-ferns, Dicksonia squarrosa, the stems of which are partly shrouded by the persistent dead fronds. These are most abundant in the flat ground at the lower part of the gully, and as they ascend the banks become reduced to solitary specimens, here and there intermixed with the more graceful Hemitelia, which becomes more abundant in the upper parts of the gully and attains large dimensions.
Interspersed amongst the scattered tree-ferns are gigantic specimens of Lomaria capensis which considerably overtop the visitor as he passes beneath them; as they ascend the banks they gradually diminish in height until they pass into the var. minor. Lomaria patersoni is plentiful and luxuriant near the head of the gully. The spaces between the larger ferns are occupied with a dense growth of Lomaria lanceolata—Pteris scaberula in the drier places. Hypolepis tenuifolia, Lomaria discolor, L. vulcanica, and other common species forming a series of contrasts in colour and habit.
The trunks of the tree-ferns are clothed with Hymenophyllum æruginosum in the most luxuriant condition, while H. flabellatum, H. tunbridgense, and Trichomanes venosum occupy similar habitats, and the translucent H.
dilatatum covers fallen logs with its delicate tracery. Numerous epiphytic species are to be seen on the higher portions, amongst which may be mentioned Asplenium falcatum, Polypodium serpens, and P. pustulatum (verum).
One charming feature remains to be stated—the profusion of mosses and Hepaticæ, large frondose species of the latter being everywhere conspicuous, their greenish-yellow tints harmonizing thoroughly with the bright green leaves of Hookeria cristata, which in these deep gullies exhibits its highest luxuriance.
The “Archdeacon's Cove” is a delightful nook on the south-eastern side of Paterson's Inlet, and can only be approached by water. On stepping out of the boat the visitor observes luxuriant plants of Lomaria dura and L. banksii, but for some time sees no indication of the rich treat awaiting him. Proceeding for a few chains along a narrow creek, Lomaria capensis is found in great luxuriance, and almost suddenly daylight is diminished by the narrowing width of the ravine and the increasing height of the cliff, all being overshadowed by a dense growth of gigantic forest trees, thickly clothed with epiphytes so that the direct rays of the sun are excluded, and a constant drip falls from the branches. The eye is bewildered by the multiplicity of fern forms which emerge from the partial obscurity as it becomes accustomed to the diminished light. High up amongst the branches of an inclined trunk hangs a pale green mass, which seems strangely familiar, but which from its large size fails to be recognized until a tedious climb of the wet slippery trunk reveals it as Hymenophyllum pulcherrimum, with fronds between two and three feet in length. H. bivalve, H. multifidum, and many other congeners whose names need not be given, are found on adjacent trees, while H. dilatatum exhibits great luxuriance at their base. Presently the gully widens out and numerous tree-ferns are to be seen; but the glory of the gully consists in its grand specimens of Todea hymenophylloides and T. superba, both of which are plentiful, but the latter especially exhibits its most graceful habit and its most luxuriant growth. From a stout stem some 18″ high, a dense crown of nearly erect fronds with drooping tips is given off. They must be counted by scores: some of them are three years old, and between four and five feet in length, of a deep blackish-green. It is impossible to conceive of a more attractive fern than this, or of a greater contrast than is presented by the same species when spreading its yellowish-green fronds in open woods. Numerous specimens were observed, but only one exhibited the extreme beauty or attained the large dimensions stated.