Introduction

Pending a most desirable monographic revision of the Stictaceae of the world, an interim key has been prepared with supplementary notes to facilitate recognition of the species indigenous to New Zealand.

Stictaceae is a large and well defined family of foliose lichens widely distributed in most temperate and tropical countries but attaining maximum development in New Zealand where approximately eighty species are currently recognised though several are admittedly of doubtful validity. To this family belong many of the largest known lichens with a thallus over a square foot in area. As in the Peltigeraceae and Pannariaceae, some of the species contain a bluegreen phycobiont (alga) and others a green phycobiont. The most distinctive feature of the Stictaceae is the presence on the lower surface of most species of either cyphellae or pseudocyphellae, the former being round, concave white or brownish pits or depressions lined with non-gelatinized hyphae and bordered by a distinct rim while pseudocyphellae are minute, unbordered pores filled with loose or protruding hyphae. The lower surface is usually more or less tomentose, whereas in Parmeliae of comparable size and aspect the tomentum is replaced by warts or long, black rhizines.

In the genus Lobaria cyphellae and pseudocyphellae are lacking. Some botanists place all other species in the genus Sticta, but others place pseudocyphellate species in the genus Pseudocyphellaria. Until recently those species with a blue-greeen phycobiont were placed in Lobarina, Cyanosticta, and Stictina but as lichens are now regarded as lichenized fungi and classified as such, the algae now play no part in the taxonomy of lichen genera and these genera are merged in Lobaria, Pseudocyphellaria, and Sticta respectively..

New Zealand Stictae at maturity range from a width of 3 to 5 cm. to as much as 35 cm. With few exceptions the species are highly plastic, and the resulting polymorphism makes the delimitation of some species very difficult. Some of the earlier ‘species’, apparently autonomous, were later found to be isolated plants in a more or less continuous range of forms belonging to another highly plastic species, and it appears probable that a further reduction in the number of valid or autonomous species will result from any future monographic study.

Though Colenso, Lyall, Sinclair, Helms, and Knight forwarded copious suites of specimens to overseas botanists for determination, page 107 and where necessary description also; and though such visiting overseas botanists as Hooker, Lindsay, Berggren, Du Rietz, and others also made considerable collections, it became evident that further field study would be necessary to determine the true taxonomic status of much of the material collected. There still remains much need for a monographic study and revision of the Stictaceae of the world numbering over 400 species. Some work towards this objective had been undertaken by P. James and J. Murray, but the accidental death of Dr. Murray in a motoring accident has led to some temporary postponement of the project. The inadequate descriptions of some of the ‘species novae’ by their authors, has made their more adequate description most desirable, and in many cases a reassessment of their taxonomic status. It has to be admitted that many descriptions fail to adequately portray the distinctive features that distinguish one species from another.

Illustrative of the difficulties encountered in the taxonomy of the Stictaceae Sir J. D. Hooker once wrote, ‘I doubt if any two independent botanists working on the same material would arrive at the same conclusions.’; an observation subsequently substantiated, for even today no two authors are yet in complete agreement. Dr. W. Lauder Lindsay, a Scottish lichenologist who in 1861 spent three months in Otago studying the local flora and in particular the lichen flora of the environs of Dunedin, arrived at the conclusion that Pseudocyphellaria carpoloma, P. cellulifera, P. colensoi, P. flavicans, P. foveolata, P. impressa and P. richardii were not autonomous species but variants of one and the same species. He also regarded Sticta coriacea, P. glabra, and P. linearis as synonyms.

Similarly Babington regarded P. billardieri, P. cellulifera, P. foveolata, P. linearis and P. impressa as mere modifications of P. fossulata, and Nylander held a similar opinion. In his “Lichenes Novae Zealandiae” of 1941, Zahlbruckner relegated the following species to synonymy:—P. dissimilis (= P. cinnamomea); P. expansa (= P. glaucolurida); P. multifida (= P. psilophylla); P. parvula (= P lacera); P. physciospora (= P. impressa); and P. subvariabilis (= P. polyschista). He also (I think correctly) restored P. aurigera and P. xantholoma to their original status as varieties of P. mougeostiana. As access to original and type specimens, almost all of which are held overseas, has not been possible, the following tentative key has been based on the published descriptions (not always adequate), on an examination of (presumably) correctly named specimens in local herbaria, and on some acquaintance with most of the species in their natural environment.

In 1949, Dr. H. H. Allan, Director of the Botany Division of the D.S.I.R. published in ‘Tuatara’ (vol. 2, pp. 97-101) a useful key to the more common species of Stictaceae indigenous to New Zealand; but, as almost half the recognised species were omitted its limitations page 108 were obvious. Most of the omitted species are included in the following key, the elimination of such as may prove to be synonyms being left to a future monographer.

Most indigenous species of Sticta have white or brownish cyphellae, while in Pseudocyphellaria the pseudocyphellae with few exceptions are yellow or white. Yellow pseudocyphellae may, however, be associated with either a yellow or a white medulla. Cephalodia are present in many species but only in such as have a green phycobiont. As a rule they are small, more or less globular bodies on or partially immersed in the thallus and containing blue-green algae.

The Stictae are variously found on bark, twigs, rock, moss or soil; most occur sometimes as epiphytes, though a number — e.g. P. cinnamomea, P. fragillima, P. crocea, P. mougeotiana — clearly prefer a rock substrate. At subalpine levels many species normally epiphytic or epilithic may be observed growing on soil, commonly in grassland. The following have been so observed by Thomson, Galloway, and the writer — Lobaria laetevirens, Sticta ftlix, S. limbata, Pesudocyphellaria carpoloma, P. aurata, P. crocea, P. delisea, P. durvillei, P. endochrysea, P. flavicans, P. foveolata, P. freycinetii, P. gilva, P. lechleri and P. tnougeotiana; while Thomson lists twenty three species as having been collected by him on a rock substrate.

Most species are photophilous and avoid deep shade. In the dense forests of Westland and Fiordland, the commonest species on the trunks are P. glabra, P. homeophylla, P. billardieri, Sticta filix, and S. latifrons. The greatest concentration of species occurs in areas with an annual rainfall of not less than 30 to 40 inches evenly distributed over the year. Thus while fifty species are known from the environs of Dunedin with an annual rainfall of over thirty inches, only one species (P. mougeotiana) is found in parts of Central Otago where the annual rainfall is under twenty inches.

Among species recorded from New Zealand are a number wrongly determined, as S. orygmaea for P. coronata, S. filicina for S. filix, S. quercizans for S. weigelii, Lobaria herbacea for L. laetevirens, L. amplissima for L. laciniata. For lack of adequate detail the species known as Sticta elaphocera and Pseudocyphellaria dictyophora have not been included in the following key. The former has been regarded as a variety of Sticta coriacea and like it has a hairy margin. It bears some resemblance to S. damaecornis. The latter is a very small species found by Colenso near Napier, only about an inch in width, minutely isidiate, and possessing a blue-green phycobiont. Both plants lacked soredia, cyphellae and pseudocyphellae as well as apothecia.

Other recorded species omitted from the key include Pseudocyphellaria flotowiana, P. coronatoides, P. insculpta, P. linearis, and P. physciospora for the following reasons. According to James, who has examined part of the type collection, P. flotowiana is identical with P. billardieri. P. linearis and P. physciospora are regarded as page 109 mere forms of P. fossulata, the former distinguished solely by the smaller dimensions and less foveolate surface, and the latter by the more physcioid characters of the spores. The writer has failed to locate the description of P. coronatoides, the determination given to a plant growing on Leptospermum at Boulder Hill in Otago and secured by J. Scott Thomson. P. insculpta is a dubious inhabitant of New Zealand which scarcely differs from P. cinnamomea save in its dissected margins. Because the species most commonly labelled Lobaria glomulifera and L. montagnei are sometimes pseudocyphellate, they have been placed as species of Pseudocyphellaria, notwithstanding their parmelioid apothecia; and as already indicated P. aurigera and P. xantholoma are deemed mere varieties of P. mougeotiana.

Until some species have been more accurately defined, it is doubtful if any key can adequately distinguish the allied ‘species’ (?) in several groups of Stictae; hence when using the key that follows due allowance must be made for the plasticity of many species and for the resultant polymorphism which applies to almost every feature of the thallus; its colour, form, and size; its smoothness, rugosity or foveolation; the density (or absence) of tomentum on the lower surface; the degree of dissection of the thallus or thallus margin; or the concentration of isidia, soredia, cephalodia, cyphellae, pseudocyphellae, apothecia, or spermagonia. Thus it may be anticipated that two specimens of the same species may well present a very different aspect.

Key to Stictaceae of New Zealand

Indigenous Stictaceae with features in Common

(L. = Lobaria p. = Pseudocyphellaria S. = Sticta)

Stictae with Yellow Medulla

• P. colensoi

• P. coronata

• P. aurata

• P. durvillei

• P. endochrysea

• P. flavicans

• P. glaucolurida

• P. grandis

• P. hirta

• P. rubella

Stictae with Yellow Pseudocyphellae

• P. astictina

• P. aurata

• P. carpoloma

• P. colensoi

• P. coronata

• P. crocata

• P. durvillei

• P. endochrysea

• P. expansa

• P. flavicans

• P. gilva

• P. glaucolurida

• P. grandis

• P. granulata

• P. hirsuta

• P. hirta

• P. impressa

• P. lechleri

• P. lorifera

• P. mougeotiana

• P. multifida

• P. obvoluta

• P. rubella

Stictae with Isidia

• S. fuliginosa

• S. weigelii

• P. chloroleuca

• P. delisea

• P. dissimilis (sometimes)

• P. diversa

• P. durvillei

• P. flavicans

• P. freycinetii

• P. granulata

• P. hirta

• P. hookeri

• P. polyschista

• P. psilophylla

Stictae with Soredia

• S. efflorescens

• S. limbata

• P. argyracea

• P. aurata

• P. cellulifera

• P. colensoi

• P. condensata

• P. crocata

• P. dozyana

• P. granulata

• P. intricata

• P. mougeotiana

• P. rubella

• P. thouarsii

• L. scrobiculata

Stictae Tomentose or Hirsute on upper Surface

• *S. coriacea

• *S. subcoriacea

• *P. expansa

• *P. grandis

• P. hirsuta

• P. muelleriana

• P. obvoluta

• P. rubella

• * = submarginal only

Stictae obviously Foveolate or Scrobiculate

• S. fuliginosa

• P. billardieri

• P. carpoloma

• P. cellulifera

• P. colensoi

• P. coronata

• P. dozyana

• P. durvillei

• P. fossulata

• P. foveolata

• P. freycinetii

• P. glaucolurida

• P. grandis

• P. homeophylla

• P. hookeri

• P. impressa

• P. lorifera

• P. richardii

• L. retigera

• L. scrobiculata

Stictae with Black Apothecia

• P. carpoloma

• P. cinnamomea

• P. condensata

• P. crocata

• P. elatior

• P. expansa

• P. fossulata

• P. faveolata

• P. glaucolurida

• P. hookeri

• P. impressa

• P. lechleri

• P. montagnei

• P. muelleriana

• P. richardii