The New Zealand Forms of Corybas Salisb.
[Read before the Auckland Institute, October 16, 1946; received by Editor, January 9, 1947; issued separately, September, 1947.]
In Trans. R.S.N.Z., 75, 1945, 367, the writer gave a note on the synonomy, the names and a key to the species as they stand under the genus Corybas. Since he is not permitted to repeat that matter in the present paper, the two sections of the review must be read in conjunction. Unless otherwise indicated, the descriptions and plates have been drawn up from living material collected by the writer. The numbers quoted in the distribution refer to Cockayne's Botanical Districts. Cockayne has been followed also in the treatment of the compound species, and the creation of a varietal name for the erstwhile type form.
Corybas was first found in Australia by Robert Brown, who, discovering three species, named them tentatively Corysanthes. This was during the Flinders Survey Expedition, 1801–5. Brown, then Keeper of the Botanical Collections in the British Museum, accompanied the Survey as Naturalist. Brown collected, Ferdinand Bauer sketched, and between them they amassed such a quantity of botanical material that it was not until 1810 that the results of Brown's work could be published. This was the first official appearance of Corysanthes. (Prodr. Fl. Nov. Holl., etc., 1810, 328.)
Meanwhile R. A. Salisbury had surreptitiously copied Bauer's drawing of Corysanthes bicalcarata (a drawing with Brown's name attached), made an inadequate description from the sketch, and published it under the name Corybas aconitiflorus. (Parad. Lond., 1805, t., 83.) Brown, eventually publishing Corysanthes in his Prodromus, and pardonably annoyed by Salisbury's behaviour, added a paragraph of caustic comment, condemning his ethics and refusing to recognise the priority of his publication. This argument of Brown's was upheld, and Corysanthes came into general use. Later, when the question of prioritv became important to taxonomy, various efforts (primarily by H. G. Reichenbach) were made to revive Corybas. So vigorous were the objections to this course that it was not until recently that the International Council of Botanical Nomenclature finally gave the decision in favour of Salisbury's name. This decision was conveyed in a letter from Dr. T. A. Sprague, of Kew, to the South Australian botanist, J. M. Black.
The genus as a whole appears to have had its beginnings in the Himalayan foothills, and drifted thence into Malaya and Australia. The Australian forms probably became isolated very early,
and have differentiated independently. The Malayan forms evolved along a rather more elaborate line, passing S.E. through New Guinea to New Zealand and missing Australia entirely. Of the 7 New Zealand species, 3 belong to the Australian group and 4 to the Malayan. Two of the former group (C. aconitiflorus and C. unguiculatus) were most probably windborne originally, across the Tasman, while the third (C. carsei) is an endemic species derived from C. unguiculatus.
It has been suggested that C. aconitiflorus, with its spurred labellum, represents one of the survivors of a very primitive group. (The Australian C. undulatus, having both spurs and auricles, represents perhaps an intermediate stage.) The auriculate forms appear to be evolved from the early spurred forms, and the more elaborate species of the former, with long segments, to be more recent than those with short segments. Of the species, C. carsei is obviously derived from C. unguiculatus by an extension of the labellar calli, just as in Australia, C. unguiculatus gave rise to C. fordhamii Rupp. by a reduction of the calli. C. macranthus, trilobus and rivularis have the same type of column and were all probably derived from an early form of C. trilobus. In the absence of a working knowledge of the Malayan species, little can be said of the affinities of C. oblongus, although it appears to some extent to be intermediate between the Australian and Malayan groups.
In those species with a wide range, the time of flowering varies considerably with latitude and with altitude. Thus at sea level in the Auckland district, C. trilobus flowers during early June, oblongus and macranthus typicus during September—October, and rivularis during September. On the Volcanic Plateau, at 4,000 feet, C. macranthus longipetalus flowers during early September, trilobus during early December, macranthus typicus from November to January, and oblongus from January to February. At sea level in Stewart Island C. trilobus flowers from August to September, rivularis during October, and oblongus and macranthus typicus during November.
In the descriptions the overall flowering period of each species is given irrespective of latitude or altitude.
Insects are believed to be the fertilising agents in Corybas, but little information is available concerning the exact procedure. Plants of C. trilobus, grown under controlled conditions by the writer, produced ripe capsules by self-fertilisation, but whether this method is at all common in nature is rather doubted. In most of the species the flowers are borne on a few small plants which appear early in the season. After a week or so, larger flowerless plants appear, these latter forming, especially in the case of C. trilobus and macranthus, the greater part of the colony. It has been estimated that in an average colony of C. trilobus only 1 per cent. of the plants bear flowers. Of this 1 per cent. perhaps a twentieth produce ripe capsules. As a consequence, or perhaps as a contributory cause, vegetative
propagation is largely resorted to. Each flowerless plant produces several terminal tubers on long root fibres. Thus in the course of two seasons one plant may become as many as six new plants. C. macranthus has this increase by tubers down to such an art that in three colonies observed by the writer over a period of years, no flowers appeared at all.
These have been recorded between C. macranthus and C. trilobus. Specimens collected by the writer in the Nothofagus forests to the south and east of Mt. Ruapehu, and in the Podocarpus copses of the Waiouru Hills also suggest a cross between these species. Until they can be studied under controlled cultivation and artificially cross-pollinated nothing definite can be said concerning the limits of the two forms. These experiments are under way and will be described in a future paper. It is worth noting that these apparent hybrids have only been recorded from areas where the flowering seasons of the two species overlap.
Epharmony and Variation.—As a rule dense shade and damp produce large, flaccid leaves, long petioles and peduncles and large more or less translucent flowers. Conversely, bright light, especially in dry areas, induces smaller succulent sessile leaves and small sessile flowers. At high altitudes (as also at sea level in southern latitudes) the flowers are usually larger and more brightly coloured than are their counterparts at sea level. The leaves of all the species often show symmetrical constrictions, single or double. Specimens of this type in C. macranthus typicus formed the basis of Cheeseman's Corysanthes rotundifolia var. pandurata, which is now a synonym.
(Corysanthes R. Br.—Nematoceras Hook. f.)
Tiny terrestial succulent herbs, either massed in large colonies or scattered. Root of small globular tubers on slender wandering caudicles. Leaf solitary or very rarely 2, sessile or petiolate, cordate, orbicular, oblong or ovate-acuminate. Floral bract acute to subulate, often with a small secondary bract at the anterior base of the ovary. Flowers 1–2, reddish-purple, grey or white, variously marked; at first usually sessile on the leaf but afterwards raised by the elongation of the peduncle following fertilisation. Dorsal sepal clawed at the base, more or less cucullate, incurved or horizontal. Lateral sepals either minute or elongated into filiform caudae. Petals similar, smaller, sometimes wanting. Labellum tubular, with a rounded auricle at the base on either side of the column, or with hollow conical spurs, or with both auricles and spurs. Distal portion (lamina) often expended, with entire, fimbriate or variously lobed margins. Column very short, stout, occasionally winged, with a prominent callus at the base. Stigma broad, placed immediately beneath the rostellum. Anther large, terminal, erect, 2-celled. Pollinia 4. Pollen granular or mealy.
A genus of rather more than 50 species, ranging from India to the Philippines, and through Malaya to Australia, New Guinea. New
1. acomtiflorus Salisb.
A.—Plant, natural size B.—Labellum from the front. C.—Leaf from above. D.—Seeding stage.
2. C. unguiculatus (R.Br.) Reichb. f.
E.—Plant, natural size. F.—Leaf showing constrictions. G.—Labellum from above (opened out). H.—2-leaved juvenile stage. J.—Column (after Smith).
3. C. carsei (Cheesmn.) Hh.
K.—Plant, natural size. L—Labellum from above (opened out). M.—Column showing sepals and petals (after Nicholls).
Zealand and Polynesia. Of the 7 New Zealand species, 2 are common Australian plants, and the remaining 5 endemic.
For a key to the New Zealand species refer to Hatch. Trans. R.S.N.Z., 75, 1945, 368.
1. Corybas aconitiflorus Salisb., Parad. Lond., 1805, t., 83 (in-correctly figured) Hatch, Trans. R.S.N.Z., 75, 1945, 367.
Up to 4 cm. high. Leaf solitary, sessile, up to 15 mm. long by 12 mm. broad, ovate- to orbicular-cordate, apiculate, repand, glaucous above, silvery below, veining vaguely embossed. Floral bract acuminate, repand, secondary bract often wanting. Flowers 1–2, sessile, purplish. Dorsal sepal very large, broadly cucullate, usually horizontal, the acute tip incurved. Lateral sepals minute, subulate, erect. Petals usually wanting, where present very minute, deflexed. Labellum largely hidden beneath the dorsal sepal. Base with 2 conical spurs. Lamina abruptly recurved. Column stout, erect, basal callus large. Anther proportionately very large. Seeding peduncle up to 15 cm.
Distribution. Australia—Queensland, N.S.W., Victoria, Tasmania; not uncommon. New Zealand—2, 3a, fairly frequent throughout in old-established Leptospermum scrub; 3b, Clevedon; 8, 1945 (R. McKenzic); 10, Westport (W. Townson); 6, New Plymouth, 5, 1946 (O. E. Gibson).
Flowers May to August. Sea level to 1,500 feet. Small groups or scattered. A very large, white-flowered form occurs in N.S.W.
2. Corybas unguiculatus (R. Br.) Rcichb. f. Beitr. Syst. Pfl., 43. Hatch, Trans. R.S.N.Z., 75, 1945, 367.
Up to 8 cm. high. Leaves 2 in the juvenile, usually but not invariably solitary in the adult, up to 3 cm. long by 3 cm. broad, broadly cordate, acute or obtuse, sessile. Floral and secondary bracts acute. Flowers 1–2, shortly pedunculate, greenish purple to grey, often deflexed. Dorsal sepal narrow at the base, broadening towards the obtuse tip. Lateral sepals linear-subulate, about half the length of the labellum. Petals similar, smaller. Labellum with 2 rounded auricles at the base. Lamina tubular, the anterior margins more or less denticulate. Labellar calli confined to the median line and extending back into the throat. Column stout, erect, basal callus prominent, another recurved at the tip. Seeding peduncle up to 10 cm.
Distribution. Australia—N.S.W., Victoria, S.A., Tasmania; rather rare. New Zealand—2, Kaitaia, 8, 1897–1900 (R. H. Matthews); Fairburn, 7, 1907 (H. Carse); Oinu, 6, 1920–4 (H. B. Matthews); Aponga (A. Thompson); 3a, Aratia, 10, 1944 (P. Hynes).
Flowers July—August. Sea level to 1,000 feet. Small groups.
Australian specimens have much larger flowers and smaller leaves than do those from New Zealand. The 2-leaved juvenile stage is not so common in Australia, but it has been recorded. (Rupp, Guide Orch. N.S.W., 1930, 92.) The accompanying illustration has been drawn up from the photographs of living plants prepared by the late H. B. Matthews The description has been adapted from Cheese-man (Trans. N.Z. Inst., 31, 1899, 351) and carefully checked against
the above photographs and recent descriptions of living Australian plants, and compared with dried specimens from both sides of the Tasman.
3. Corybas carsei (Cheesmn.) Hh. Trans. R.S.N.Z., 75, 1945, 367.
Up to 3 cm. high. Leaf solitary, sessile, up to 25 mm. long by 19 mm. broad, ovate- to orbicular-cordate. Floral and secondary bracts acute. Flowers 1–2, similar to but rather smaller than those of C. unguiculatus, from which it differs in the projecting tip to the lamina of the labellum; the labellar calli extending on either side of the median line but not back into the throat; the slender incurved column with an inconspicuous basal callus and an erect tip to the anther. Seeding peduncle up to 6 cm.
Distribution. Endemic. 2, peaty swamps at the north end of Lake Tongonge (Kaitaia); 8, 1911 (H. Carse); 9, 1919 (H. B. Matthews); 3b, Tauhei (Morrinsville); 12, 1925 (H. Carse).
Holotype. In Herb. Carse, No. 5931/1 (Canterbury Museum), Lake Tongonge, August 25, 1911, H. Carse.
Flowers July to September, sea level. Small groups in bog association containing Lepyrodia traversii F.V.M. and Lycopodium drummondii Spring.
Very close to the Australian C. fordhamii Rupp, from which it differs only in the absence of the labellar calli. Both species are undoubtedly derived from an early form of C. unguiculatus. The accompanying illustration has been drawn from Matthews' photographs and in part from Nicholl's plate of C. fordhamii (Vict. Nat. 58, 1941, 83, t.). The description has been adapted from Cheeseman (Trans. N.Z. Inst., 44, 1911, 162) and compared with specimens in the Auckland Museum. Carse (N.Z. Journ. Sci. Tech., 8, 1926, 168) gives an interesting account of the ecology of the species and its apparent dependence upon the sedge and lycopod mentioned above.
4. Corybas oblongus (Hook. f.) Reichb. f. ibid., 67. Hatch, Trans. R.S.N.Z., 75, 1945, 367.
Up to 4 cm. high. Leaf solitary or very rarely 2, sessile, up to 5 cm. long by 3 cm. broad, ovate-oblong to nearly orbicular, apiculate, glaucous above, reddish below. Floral bract acuminate, secondary bract subulate, often foliaceous. Flowers 1–2, sessile, purplish. Dorsal sepal narrow, regular, obtuse or apiculate. Lateral sepals filiform-caudate, erect, about twice the length of the labellum. Petals similar, smaller, usually sub-erect. Labellum with 2 rounded auricles at the base. Lamina tubular, the anterior margins fimbriate, with a translucent band. Column short, stout, slightly curved at the top. Basal callus conspieuous. Seeding peduncle up to 16 cm.
Distribution. Endemic—not uncommon throughout New Zealand, Stewart, and the Auckland Islands.
Flowers September to February, sea level to 4,000 feet. Small groups or scattered. Hooker's illustration under Nematoceras oblonga, Fl. Nov. Zel., 1. 1853, 250, t. 57 b can be regarded as the hypotype of the species. An apparently isolated form, in some respects intermediate between the Malayan and Australian groups.
5. Corybas trilobus (Hook. f.) Reichb. f., l.c. Hatch, Trans. R.S.N.Z., 75, 1945, 368.
Up to 7 cm. high. Leaf solitary, petiolate, up to 15 mm. long by 25 mm. broad, reniform, trilobate, acute, light green above, silvery below, often marked with purple. Floral bract acute, secondary bract inconspicuous. Flowers solitary, sessile, purplish. Dorsal sepal rather short, orbicular-concave, more or less emarginate. Lateral sepals erect, filiform-caudate. Petals similar, smaller, often horizontal. Labellum with 2 rounded auricles at the base. Lamina expanded, deflexed, roughly circular, the margins irregularly crenulate or sometimes entire. Column short, slightly recurved. Seeding peduncle up to 20 cm.
Distribution. Endemic—throughout New Zealand and Stewart Island, locally abundant but often absent over wide areas.
Flowers June to December. Sea level to 5,000 feet. Large colonies on the forest floor.
Affinities with C. macranthus and C. rivularis. All three probably derived from a common ancestor very far back.
6. Corybas macranthus (Hook. f.) Reichb. f. l.c. A compound endemic species of 2 jordanons.
Petals hardly a third as long as the lateral sepals, labellum apiculate, obtuse or emarginate, dorsal sepal horizontal or recurved …….var. typicus
Petals as long or longer than the lateral sepals, labellum with an acuminate lobe, dorsal sepal incurved …………… var. longipetalus
a. Corybas macranthus var. typicus Hh. (Nematoceras macrantha Hook f., sens. strict.)
Up to 22 cm. high. Leaf solitary, petiolate, up to 4 cm. long by 4 cm. broad, ovate-cordate, mucronate, light green above, silvery below, often marked with purple. Floral bract acute, secondary bract similar, smaller. Flowers 1–2, sessile, purplish, green or red. Dorsal sepal acuminate, usually longer than the labellum, horizontal or recurved. Lateral sepals erect, filiform-caudate. Petals similar, about a third as long, often horizontal. Labellum with 2 rounded auricles at the base. Lamina expanded roughly funnel-shaped, the anterior margin irregularly crenulate, obtuse emarginate or apiculate. Column short, erect, or slightly incurved, the wings exceeding the anther. Seeding peduncle up to 20 cm.
Distribution. Endemic—abundant throughout New Zealand, tending to be less common in the north. Also in Stewart, Chatham, Auckland and Campbell Islands.
Flowers July to January, sea level to 5,000 feet. Large colonies on the forest floor or along the banks of rivers.
Hooker's illustration under Nematoceras macrantha (Fl. Nov. Zel., 1, 1853, 250, t. 57 a.) can be regarded as the hypotype of the species. Probably derived from an early form of C. trilobus. Occasionally the petals are furnished with irregular, fleshy lobes. Stewart Island has a beautiful pink-flowered form, morphologically identical with the normal, but which breeds true to colour-type.
b. Corybas macranthus var. longipetalus Hh. var. nov.
Macranthus typicus affinis, subsimilis. Differto sepalum dorsale incurvum; petala longissima; lamina labellae lobata et acuminata.
Up to 6 cm. high. Similar to but rather smaller than the type, and differing in the very long petals, the lobed labellum and the incurved tip to the dorsal sepal. The lateral sepals are often horizontal. Flowers red or translucent. Seeding peduncle up to 15 cm.
Distribution. Endemic—5, abundant along the banks of streams throughout the tussock hill country lying between the Moawhango and Wangaehu Rivers to the south-east of Mt. Ruapehu. 1942–5 (E. D. Hatch); 16, specimens in seed, almost certainly belonging to this variety, have been found at Butterfields Beach, Stewart Island, 11, 1946 (C. Smith); 12a, Kelly Creek, Otira River, 1, 1947 (P. Haddon-Jones).
Holotype. In Herb. Hatch, No. 563, Waitangi Stream (Wai-ouru), 3,000 feet, September 2, 1944, E. D. Hatch.
Flowers September to November, 3,000 to 4,000 feet, descending to sea level in Stewart Island. Small colonies.
Probably derived from C. macranthus typicus. The accompanying illustration can be regarded as the hypotype of the variety.
7. Corybas rivularis (A. Cunn.) Reichb. f., l.c. Hatch Trans. R.S.N.Z., 75, 1945, 368.
Up to 15 cm. high. Leaf solitary, sessile, up to 4 cm. long by 25 mm. broad, ovate-acuminate, repand, light green above, silvery beneath, with conspicuous reddish veining. Floral bract shortly caudate, secondary bract subulate. Flowers solitary, sessile, more or less translucent, with dull red striae. Dorsal sepal extended into a filiform cauda. Lateral sepals erect and very long, exceeding the flower by as much as 6 cm. Petals similar, smaller, horizontal or deflexed. Labellum with 2 rounded auricles at the base. Lamina expanded, abruptly recurved against the ovary, mucronate, irregularly fimbriate, or entire. Column short, basal callus large. Stigma orbicular, column-wings minutely denticulate and exceeding the anther. Seeding peduncle up to 18 cm
Distribution. Endemic—occasional throughout New Zealand, Stewart and the Auckland Islands. tending to be rather local.
Flowers September to November, sea level to 2,000 feet. Large colonies on the forest floor.
Probably derived from an early form of C. trilobus.
The writer wishes to express his indebtedness to Miss B. E. G. Molesworth. of the Auckland Museum, Mr. Cedric Smith, of Stewart Island, and Mr. F. W. Bartlett, of Silverdale, for much material. many notes and a great deal of assistance.