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Volume 88, 1960-61
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The Cryptogamic Flora of the Awarua Plains

By William Martin

[Read before the Otago Branch, August 11, 1959; received by the Editor, September, 1959.]

Abstract

The peat bogs of the Awarua Plains, in Southland, formerly very extensive, are fast disappearing as a result of drainage and cultivation. The plant cover contained many plants which elsewhere were always restricted to subalpine areas. These included both the flowering plants and the cryptogams, of which only the former have previously been catalogued. The present paper serves to complete a record of a unique plant formation before its final replacement and disappearance.

Prior to the European settlement of Southland and, indeed, for the first two decades of the present century, the Awarua Plains, extending from Invercargill to Bluff Harbour and for some miles to the north, was largely occupied by an extensive series of swamps and bogs covering some thousands of acres. Botanically the area held a special interest from the presence of a vegetation markedly sub-alpine in character though occurring almost at sea level. Smaller areas of a similar nature occurred as far north as Owaka, near Makarewa, and again in Stewart Island, but none were so extensive, or populated by such varied florula, even though subalpine species at sea level are still more numerous in the south of Stewart Island.

In 1927 a very comprehensive catalogue of the pteridophytes and flowering plants of the Awarua Plains was compiled by J. Crosby Smith and published in Vol. 58 of the Transactions of the New Zealand Institute; but no account of the even larger cryptogamic flora has hitherto been made, notwithstanding the rapid replacement of these bogs by arable land consequent on drainage and cultivation. In a few years the opportunity will have vanished.

L. Cockayne in “The Vegetation of New Zealand” (2nd edition, p. 202) attributes the existence of extensive areas of bog in the west and south of the South Island to “an abundant rainfall, a comparatively low summer temperature, and frequent cloudy skies”, and in the case of the Awarua Plains we might add to poor drainage owing to their low elevation above sea-level.

These Awarua Plains were occupied by a number of distinct plant associations, one of the most extensive of which had as its dominant species Donatia novaezealandiae, a species elsewhere restricted to subalpine bogs. In this association the subalpine element was strongly represented both in the phanerogamic and in the cryptogamic sections of the vegetation. The occurrence here in quantity of Herpolirion novae zealandiae, Oreostylidium subulatum, Oreobolus pectinatus, Carpha alpina, and many other species elsewhere montane and subalpine gave these bogs a unique character, as did the presence of Siphula medioxima and of Cladonia sullivani in the associated lichens. Besides the species elsewhere restricted to subalpine areas, there were numerous others which were commonest in such localities though sometimes found at lower levels.

Over much of the area, the peat, six to eight feet deep, overlies a layer of white gravel, but the depth thins out almost to vanishing point in some localities. Drainage channels have been cut and as a consequence the peat has partially dried out and greatly shrunk, leaving the Donatia cushions considerably elevated above the lowered surface. As a consequence, these have slowly died, and today scarcely a cushion remains in areas where they formerly existed in hundreds. Many of the associated

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species are also fast disappearing, and on these dried-out soils manuka (Leptospermum scoparium) is now commonly present to complete the destruction of the former cover. Extensive fires have recently swept much of the area.

As already indicated by Crosby-Smith, the distribution of the various associations is consequent very largely on the water content and degree of aeration of the peat. Much of the area south of the railway line to Bluff is occupied by fresh water and saline swamps and marsh rather than by bogs, and here Phormium and Carices are abundant but replaced by Leptocarpus simplex in the saline marshes. The only cryptograms noted in the swampy areas were Sphagnum falcatulum and S. australe and an occasional patch of Polytrichum commune.

To the north of the railway and road Donatia bog was formerly extensive, with the drier, more elevated areas occupied by tussocks of Danthonia rigida var. rubra or by Leptospermum. However, large areas were dominated by Gleichenia circinata and by Hypolaena lateriflora. On the driest ridges bracken (Pteridium esculentum) was quite common.

On the margins of the peat area the Danthonia tussocks were more massive, and the ground between them often sheltered epacrids and heaths, as well as the three species of Cladonia constituting the sub-genus Clathrina.

The Cryptogamic Florulae of the Individual Plant Associations

1. Coastal Swamps.

The saline marshes south of the railway line are occupied mainly by Leptocarpus simplex, and in these areas cryptogams are absent. The fresh water swamps further inland are populated variously by Phormium tenax, Leptospermum scoparium, or Carices, Carex geminata being the principal species. Here the only cryptogamic plants observed were the fern Blechnum procerum and three mosses, the slender Sphagnum falcatulum, the more robust S. australe, and occasionally Polytrichum commune. Hepatics, fungi and lichens were not observed.

2. Donatia Bog.

This occurs on the wettest peat soils, but two sub-associations are present. Donatia novae-zealandiae which occupied the samewhat drier, slightly elevated portions, was the dominant species in an association which included Carpha alpina, Celmisia gracilenta, Gentiana lineata, Gunnera monoica, Gunnera prorepens, Oreostylidium subulatum, Oreobolus pectinatus, and Thelymitra spp. In the wetter hollows Drosera binata, D. spathulata, Montia fontana, and Utricularia monanthos were the commoner species. The cryptogams were commoner on the drier areas, but as the two sub-associations occupied the same territory no distinction was observed and they are listed together. The Pteridophytes were the ferns Schizaea fistulosa and Lindsaya linearis, and the endemic lycopod (Lycopodium ramulosum). Sphagnum falcatulum and S. australe were abundant in the hollows and Campylopus torquatus, C. introflexus, the rare C. Kirkii, and Dicranoloma billardieri on the more elevated mounds. S. falcatulum is almost confined to stagnant pools or to ditches.

The liverwort Marchantia berteroana formed occasional patches, but fungi were few and lichens were absent with the exception of occasional clumps of Cladonia Boryi on raised mounds left by decayed Donatia cushions. A hepatic (Riccardia sp.) occurs sparingly.

3. Bogs Dominated either by Hypolaena lateriflora or by Gleichenia spp.

Hypolaena and Gleichenia usually occupied separate areas, but occasionally were intermingled on peat soils rather drier, especially in summer and autumn, than the Donatia bogs; and, as the cryptogamic plants are the same for each, they are considered together. Both Gleichenia circinata and G. microphylla are present. Where.

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their growth is dense other cryptogams are absent save for Sphagnum australe. Where the growth is short or more open, and especially on bare patches of peat the following cryptogams were collected:—Ferns: Schizaea fistulosa and Lindsaya linearis. Lycopods: Lycopodium ramulosum. Mosses: Polytrichum juniperinum, Campylopus torquatus, C. introflexus, Campylopodium euphorcladum and Dicranoloma billiardieri. Hepatics: Cephaloziella exiliflora, Chiloscyphus coalitus, Chiloscyphus normalis, Lophocolea heterophylloides, L. insularis, and on the sides of a large drain Marchantia berteroana and Riccardia sp. Fungi were not uncommon, all being agarics, but lichens were few. These were the three Cladoniae of the subgenus Clathrina—viz., Cladonia aggregata, C. retipora, and C. sullivani, together with C. cornutoradiata and C. verticillata var. evoluta.

4. Bogs with “Red Tussock” as the Dominant Species.

The grass Danthonia rigida var. rubra, generally known as the Red Tussock, occurs throughout eastern and southern Southland on open hillsides, by stream courses, in swamps, and on peat bogs, but only on such peaty areas as are not continously water-logged. In swamps it may attain an overall height of four feet or more, but normally it is less than three feet tall. In swampy areas cryptogams are few, but on drier peaty soils the three species of the sub-genus Clathrina are common associates on the ground, with several red fruited Cladonias, and the brown-fruited C. cornutoradiata, C. carassensis, C. pityrea and C. verticillata common on the mounds left by dead tussocks or less commonly on the lower “trunks” of the largest tussocks and even on the peat itself, where C. aggregata in several forms is the commonest lichen. Two agarics, one yellow with decurrent gills and the other dull red, and both fairly small, were common. Campylopus introflexus and C. torquatus cover patches of some extent, the latter almost always sterile, and with the same two Sphagna noted elsewhere comprise the moss flora. Marchantia berteroana is present but rare.

5. “Manuka” Swamp-bog.

This is the driest type of bog, and in summer the surface may be quite dry. After rain the area is really swamp rather than bog, though the soil is peat several feet deep. As areas are drained, manuka (Leptospermum scoparium) speedily spreads to areas formerly occupied by Hypolaena, Phormium or Danthonia, and rapidly overtops and kills these by exclusion of the light. On these soils it is on the shady side of the manuka groves or for a yard or so within the margin that the cryptogamic flora is most abundant. Many groves are separated from neighbouring groves by open spaces only a few yards wide. These areas often have epacrids and heaths or perhaps Hypolaena forming an open shrubbery in which cryptogamic plants are exceedingly numerous.

Where the manuka groves reach up to ten to fifteen feet in height the interior is commonly open and diffused light penetrates freely. In such stations the ferns Blechnum procerum, B. penna-marina, Histiopteris incisa, and more rarely Polystichum vestitum may be found, or even the scrambling Lycopodium volubile, seen but once by the writer. In other areas the presence in the manuka groves of dead Danthonia tussocks and decaying “flax” bushes is evidence of aggression by the manuka following the drying of the soil consequent on drainage operations. Where the manuka is under ten feet tall the penetration of light is difficult and no crytogams are encountered save for a distance of two or three feet within the margin of the grove. This is a very common location for Cladonia retipora—the Coral Lichen, and for C. leptoclada and C. alpestris; less commonly C. crispata, C. Boryi, and C. cornutoradiata occur in this station. C. aggregata in two principal forms is also found here but is commoner in areas just clear of the manuka.

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In the shade of the manuka in particular, but also on bare peat of the open spaces the following Cladonia species occur in great quantity, especially in areas bordering the road to Awarua Bay for a mile from the Bay itself. Commonest of all are Cladonia deformis var. cyathiformis, a red-fruited species with tall trumpet-shaped podetia, and C. aggregata. Other species of section Coccifera include C. didyma, C. macilenta, C. Floerkeana, C. vulcanica (?) and more rarely C. digitata var. monstrosa. The representatives of section Chasmaria are C. carassensis, C. crispata, C. scabriuscula. C. Boryi and an undetermined Cladonia are locally common on bare peat.

Of the section Thallostelides the usual species are C. chlorophaea, C. fimbriata and C. pyxidata with trumpet-shaped podetia, C. pityrea, C. cornutoradiata in several forms, C. cervicornis, C. gracilis (two forms), and C. verticillata var. evoluta. All three species of the subgenus Clathrina are abundant. C. sullivani is here a short grey-green plant growing in compact tufts quite unlike the usual brown or brown and black forms that are commonest in subalpine habitats. Furthermore the black lining of the central canal may be absent, and some plants approximate closely to forms of C. aggregata. C. sullivani, however, is the only species which develops divaricatic acid. This very distinct form occurs widely in Southland.

The other Cladonia sections are represented by (1) Unciales—C. Boryi and an undetermined species; (2) Foliaceae—C. foliaceae var. alcicornis; (3) Podostelides—C. cariosa; (4) Ochroleucae—C. carneola, a subalpine species obtained near Fortrose by J. Scott Thomson, but not observed by the writer.

Other epigean lichens from this zone include Baeomyces heteromorphus, Sticta crocata (more usually a lithophyte or epiphyte) and the only known collection of Thelidea corrugata from the New Zealand mainland. At the bases of manuka on wet soil Peltigera polydactyla var. polydactyloides is quite common.

On the bases and stems of the manuka the mosses Sematophyllum contiguum and Lembophyllum clandestinum were observed, and on the ground amongst Cassinia, Hypnum cupressiforme and Thuidium furfurosum were abundant. Ceratodon purpureus is common on dry peat soils, and the small Lycopodium ramulosum is plentiful on the wetter areas, sometimes prostrate but more often semi-erect and fruiting freely.

Fungi are not uncommon on the peat, especially a bright yellow Clavaria (?) a small yellow agaric (Omphalia?), and a tufted species with stout stems but very small pilei, the whole dingy brown in colour. Two Caloceras and Crucibulum vulgare are present on rotting stems of manuka.

Hepatics were identical with those listed for the Hypolaena bogs.

Classified List of Cryptogamic Species

Filices

Blechnum banksii Mett. Recorded by Crosby Smith; not seen by the writer.

  • —penna-marina Kuhn.

  • —procerum (Forst. f.) Labill.

  • Gleichenia circinata (Sw.) C. Christen. var.

  • —microphylla (R. Br.) C. Christen.

  • Histiopteris incisa J. Smith.

  • Lindsaya linearis Swartz.

  • Ophioglossum pedunculosum Desv. Recorded by Crosby Smith; not seen by the writer.

  • Pteridium esculentum (Forst.) Diels.

  • Polystichum vestitum Presl.

  • Schizaea fistulosa

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Lycopodiaceae

  • Lycopodium ramulosum T. Kirk.

  • —volubile Forst. f.

Muscinae

  • Bryum sp.

  • —truncorum Brid.

  • Campylopus introflexus (Hedw.) Mitt.

  • —kirkii Mitt. apud Beckett.

  • —torquatus (Mitt.) Jaeg.

  • Campylopodium euphorocladum (C. M.) Besch.

  • Dicranoloma billardieri (Schwaegr.) Par.

  • Hypnum cupressiforme Hedw.

  • Lembophyllum clandestinum (H. f. & W.) Lindb.

  • Leptobryum pyriforme (Hedw.) Schimp.

  • Polytrichum commune Hedw.

  • —juniperinum Wild.

  • Sematophyllum contiguum (H. f. & W.) Mitt.

  • Sphagnum australe Mitt.

  • —falcatulum Besch.

  • Tayloria purpurascens (H. f. & W.) Broth.

  • Thuidium furfurosum (H. f. & W.) Jaeg.

Hepaticae

  • Cephaloziella exiliflora (Tayl.) Spreng.

  • Chiloscyplius coalitus (Hook.) Nees.

  • —normalis Hodgs.

  • Lepidozia compacta St.

  • —calcarata St. (?)

  • —Kirkii St. var.

  • Lophocolea insularis St.

  • —heterophylloides Syn. Hep.

  • Marchantia berteroana Lehm. et Lindenb.

  • Riccardia sp.

Lichenae

  • Cladoniaceae.

  • A. Genus Cladonia Hill. Subgenus Eucladonia Mattick.

Section 1. Cocciferae.

  • Cladonia deformis (Hoffm.) f. cyathiformis Sandst.

  • —didyma (Fèe) Vainio.

  • —digitata Schaer. f. monstrosa (Ach.) Vain.

  • —floerkeana (Fr.) Sommerf. f. carcata (Ach.) Vain.

  • —  —f. intermedia Hepp.

  • —macilenta (Hoffm.) Nyl.

  • —pleurota (Flk.) Schaer.

  • —vulcanica Zoll. et Mor (?).

Section 2. Foliosae.

  • Cladonia foliacca (Huds.) Schaer. var. alcicornis (Light f.) Schaer.

Section 3. Ochroleucae.

  • Cladonia carncola Fr. Obtained near Fortrose by J. Scott Thomson.

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Section 4. Podostelides.

  • Cladonia cariosa (Ach.) Spreng.

  • —sp. (undetermined).

Section 5. Thallostelides

  • Cladonia borbonica (Del.) Nyl.

  • —cervicornis Schaer.

  • —chlorophaea (Flk.) Spreng.

  • —cornuta (L.) Schaer.

  • —cornutoradiata (Coem.) Sandst. f. subulata (L.) Sandst.

  • —f. furcellata Sandst.

  • —f. radiata (Schreb.) Sandst.

  • —f. repititoprolifera Sandst.

  • —degenerans (Flk.) Spreng. f. euphorea (Ach.) Flot.

  • —fimbriata (L.) Fr.

  • —gracilis (L.) Willd. var. chordalis (Flk.) Schaer.

  • —var. dilatata (Hoffm.) Vain. f. dilacerata (Flk.) Vain.

  • —pityrea (Flk.) Vain. f. phyllophora (Mudd.) Vain.

  • —f. (?)

  • —f. subacuta Vain.

  • —pyxidata (L.) Fr.

  • —verticillata (Hoffm.) Schaer. var. evoluta Th. Fr.

  • —f. apoticta (Ach.) Vain.

  • —f. phyllocephala Flk.

Section 6. Chasmariae.

  • Cladonia carassensis Vain.

  • —Crispata (Ach.) Flot.

  • —sp. nov. (?)

  • —scabriuscula (Del.) Leight.

Section 7. Unciales.

  • Cladonia boryi Tuck. f. lacunosa Tuck (?).

Section 8. Cladinae.

  • Cladonia alpestris (L.) Rabenh. (This may prove to be Cl. alpestroides Des. Abb.)

  • —leptoclada Des Abb.

  • Subgenus: Clathrina.

  • Cladonia aggregata (Sw.) Ach. (forms).

  • —retipora Flk.

  • —sullivani Müll. Arg. f. nov.

(B) Other Genera.

  • Baeomyces heteromorphus (Bab.) Nyl.

  • Siphula medioxima Nyl. (?).

  • Stereocaulon corticatulum Nyl.

  • Peltigeraceae.

  • Peltigera polydactyla Hoff. var. polydactyloides Nyl. (?)

  • Stictaceae.

  • Sticta crocata Ach.

  • Pannariaceae.

  • Thelidea corrugata Hue. A subantarctic species, not hitherto observed on the mainland of New Zealand.

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Fungi

A parcel of fungi was forwarded for determination to a specialist, who had meanwhile left for England. The full list of a dozen or so species cannot therefore be listed; and, in any case, owing to the spasmodic fruiting of these plants, the collection was doubtless far from complete. It included, however, Thelephora terrestris from the upper margin of a deep drain cut through the peat; a small, unbranched, sulphur yellow Clavaria, 1–2 cm tall; two species of Calocera from dead manuka stems; Crucibulum vulgare from the same habitat; and a number of agarics.

Acknowledgments

The author is indebted to Mr. K. W. Allison for determining the hepaticae and several mosses, and to Dr. James Murray for the determination of several lichens.

William Martin,


27 Merchiston Street,
Dunedin E. 1., N. Z.

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