Other formats

    TEI XML file   ePub eBook file  


    mail icontwitter iconBlogspot iconrss icon

Tuatara: Volume 13, Issue 2, July 1965

The Lichen Flora of New Zealand

page 112

The Lichen Flora of New Zealand


The Following Notes should be read in conjunction with ‘Some Facts About Lichens’ in Vol. 11, Part 1 of ‘Tuatara’ by Barbara J. Williams and Keys to New Zealand Lichen Genera’ in Volumes 10 and 11 by Dr. James Murray, thereby avoiding unnecessary repetition.

Some species of lichen range over most of the land masses of the earth, others are restricted to large but usually fairly well defined areas, and yet others have quite a small range of distribution. Within such areas most species are only to be found on specific substrata such as leaves, twigs, tree trunks, clay banks, peat soils, etc., though not a few may occur on more than one substratum. Each species will be located only where the environment is congenial to its growth requirements, for which reason many lichens are commonly associated. Many species are restricted to montane and subalpine habitats, others to the lowlands, and still others range widely from sea-level to subalpine habitats.

New Zealand lichens, in the light of present knowledge, number over 1300 species grouped into over 150 genera in approximately 43 families. Many are so polymorphic as to make their delimitation difficult and it may well be that some given specific rank may prove to be synonyms. In any case it is clear that many species still await discovery and description and it seems safe to predict that the New Zealand lichen flora may exceed 1500 species.

Indigenous species having a more or less cosmopolitan distribution are fairly numerous, examples being the conspicuos yellow-green Rhizocarpon geographicum abundant on subalpine rocks, the brown-fruited pyxiecup (Cladonia pyxidata), or the dog-lichen (Peltigera canina). Of the many species apparently restricted to Australasia Cladia retipora, Cladia sullivanii, and Parmelia tasmaniae are well-known examples; and included among hundreds of endemic species we may list Cladonia enantia, C. murrayi. C. neozelandica, and C. southlandica to cite those of a single genus. Further research in Australia and Tasmania may well, however, eliminate a number as endemic species.

So far as growth forms are concerned crustose lichens exceed all others combined, and occur in most situations and on most substrata. Foliose lichens are most numerous and largest where the air is moist and still, as in the forest interior, yet some occur on exposed subalpine rocks. A majority of the fruticose lichens page 113 grow on earth or on posts, telegraph poles, or on trees in the open, while squamulose genera such as Psoroma and Pannaria are most commonly located on bark within the forest.

Epiphytic Lichens

Hundreds of lichens are to be found only on the bark of trees and shrubs, and seven or eight New Zealand genera are represented only on leaves of flowering plants or ferns. Different associations occur on the trunks of forest trees, and on the canopy branches and twigs. Limitations of space prevent more than general reference to these but the most numerous and conspicuous lichens on the lower trunks and limbs of trees belong to the genas Sticta, so named in allusion to the tiny pits dotted over the lower surface. Among the seventy-five New Zealand species at present recognized are some of the largest lichens known, with a thallus surface often exceeding a square foot in area. Such include Sticta impressa, S. foveolata, S. coronata, and a number of others. Associated lichens include species of the following genera: Menegazzia, Sphaeroma, Pertusaria, Coenogonium, Megalospora, Collema, Leptogium, and Sphaerophorus. Nephroma australe occurs here and much resembles a species of Sticta but is recognized immediately by the flat, reddish-brown apothecia which occur on the underside of the marginal lobes. Myxodictyon chrysostictum and Thelotrema lepadinum are other common species on this substratum.

Many distinct associations occur on the upper branches and twigs involving such genera as Bacidia, Catillaria, Lecidea, Lecanora, Pyrenula, Arthonia, Pertusaria, and Buellia, all crustose in life-form. The upper branches in subalpine beech forests are often so festooned with species of Usnea as to be visible from distances of a mile or more. Foliose lichens occur but are relatively rare.

Trees on the forest margin or growing in the open may include Parmelias and Hypogymnias among their epiphytes these being rare or absent within the forest. On smooth-barked trees and shrubs ‘script’ lichens belonging to the families Graphidaceae and Opegraphidaceae are numerous, other genera to be found here including Usnea, Ramalina, Haematomma, Teloschistes, etc., not to be found in the shade of the forest interior.

Commonly found growing on mosses overlying bark or rock are such species as Coccocarpia cronia, and species of Leptogium or Peltigera.

Saxicolous Lichens

Rock-inhabiting lichens constitute the largest section of the lichen flora of New Zealand. Some lichens are to be found only page 114 on limestone as for example Blastenia alboflavida, Caloplaca scott-thomsoni, or Placynthium nigrum. Many species are restricted to montane or subalpine rocks. This applies to all species of Neuropogon, Umbilicaria, Omphalodiscus, Agyrophora, Lasallia, Alectoria, and Cetraria and to several species of Parmeliella. The schist rocks of Central Otago have a copious covering of lichens on their tops and shaded sides of which the majority are species of Parmelia including Parmelia caperata, P. conspersa, P. perlata, P. arnoldii, P. signifera, P. tasmanica, P. rudecta and others including several belonging to the section Melaenoparmelia as e.g. P. epheboides. Associated with these are Pertusaria subverrucosa, Lecanora atra. Sticta aurata, Cladia aggregata, Usnea glomellifera, and at the upper levels Umbilicaria polyphylla. Over much of New Zealand Stereocaulon corticatulum and S. ramulosum occur on rocky roadside banks, or on stony slopes and the tiny S. gregarium or S. caespitosum on subalpine rocks.

Lichens of the genus Verrucaria likewise Xanthoria parietina are abundant on coastal rocks and cliffs, while Lichina pygmaea var. intermedia is only to be found on rocks subject to immersion at high tide.

Epigean Lichens

Ground dwelling lichens usually occur only on specific types of soil as clay banks, heath soils, stony soils, peat, etc., though some species occur on more types of soil than one. Lichens are few on the forest floor and include Sphaerophorus tener and various species of Peltigera. Manuka heaths often have a rich lichen flora in which lichens of the genus Cladonia and of Cladia predominate. Cladia retipora, Cladia aggregata, Cladonia gracilis var. chordalis, Cladonia verticillata, Cladonia cornutoradiata, and the bushy Cladonia leptoclada, as well as forms of Cladonia capitellata are perhaps the commonest species. In some areas the scarlet-fruited Cladonia floerkeana is abundant.

On drained peat soils such as are abundant on the Awarua Plains of Southland Cladonias in great variety are sometimes observed, two of the most conspicuous because of their bright scarlet fruits being var. crenulata of Cladonia deformis and C. vulcanica. Indeed in this area over 25 species of Cladonia have been catalogued. All three species of Cladia occur here, Cladia sullivanii by its lowland variety compacta.

Lichens of clay banks include Cladonia fimbriata, C. pyxidata, C. enantia, C. neo-zelandica, C. cornutoradiata and several others as well as Baeomyces fungoides and B. heteromorphus. Near Greymouth a common member is Cladonia pityrea.

page 115

Lignicolous Lichens

Some lichens are rarely found other than on logs or posts. Such include the various tiny species of Calicium and of Coniocybe, numerous species of Lecidea and related genera usually on bare wood. On logs in early decay common lichens are Cladonia macilenta, C. bacillaris, and C. pleurota all red-fruited. Cladonia coccifera also occurs on tree stumps but is quite rare in most districts. In the Eglington Valley in Otago beech stumps carry a copious mantle of Cladonias in which C. scabriuscula is one of the most common. Many Parmelias grow on wood but are rarely restricted to this substratum. Posts and telegraph poles in the wetter areas often are infested with species of Usnea and more rarely of Ramalina.

Tussock Grasslands

In subalpine grasslands as well as in boggy soils and fellfield the ‘worm’ lichens (Thamnolia vermicularis and T. subvermicularis) are common species as also is Siphula medioxima. Both are white lichens, the former with tapering cylindrical stems and the latter with chalky white flat thalli. On the dead bases of former tussocks Cladonia subdigitata is a very common lichen but other species also occur. On the drier grasslands a very common lichen is Chondropsis semiviridis a small yellowish species much crisped in dry weather which lies unattached on the surface usually in vast numbers as in Central Otago and Canterbury.

Other Substrata

Several Parmelias are commonly found on the tiled roofs of houses, and have also been seen on asphalt in the streets of Auckland City. Various crustose species are quite common on many city buildings both of wood and stone, and there is a copious lichen flora on the stems of mangrove growing in mud along the Auckland coast. A species of Mastodia has been noted on the nitrogenous soils close to the nesting sites of petrels. The lichen flora of New Zealand offers a vast field of research for future students.