Flora of New Zealand Series

Thallus foliose, heteromerous, dorsiventral, lobate, spreading or sometimes stalked with a fruticose, erect, monophyllous to polyphyllous, frond sometimes arising from a ± woody, spreading holdfast, ± loosely attached, 2-30 cm diam., or larger, corticolous, rarely saxicolous. Lobes ± dichotomously branching to broad, rounded, irregular, complex, overlapping to variously incised, often lacerate-notched, with or without isidia or phyllidia, tough, coriaceous to fragile, thin or thick. Upper surface smooth, wrinkled or ridged, rarely faveolate-impressed, shining or dull, often maculate, scabrid or hairy, isidiate or sorediate, without pseudocyphellae. Medulla white. Photobiont green Trebouxia or Myrmecia, or blue-green (Nostoc). Internal or erumpent cephalodia (Nostoc) usually present in species with green photobiont. Lower surface pale or dark, glabrous, or tomentose, cyphellae always present. Apothecia hemiangiocarpic, laminal, rarely marginal, sessile or pedicellate, margins entire or crenate, disc matt or shining, rarely pruinose, thalline exciple well-developed, smooth or verrucose-areolate or hairy. Ascospores 8 per ascus, colourless or brown, 1-3- septate (rarely 4-7-septate). Pycnidia often frequent, immersed, punctate to subglobose.

Sticta, included in the family Lobariaceae, is a cosmopolitan genus of c. 200 species, most richly developed in tropical regions. Although superficially similar in both morphology and habitat requirements to Lobaria and Pseudocyphellaria, species of Sticta are readily distinguished by the presence of cyphellae on the lower surface and a medullary chemistry deficient in acetone-soluble substances such as depsides, depsidones or triterpenoids, but rich in water-soluble compounds such as simple sugars, polyhydric alcohols, methylamine and trimethylamine, the latter often imparting a fishy smell to damp thalli, especially in species having a blue-green photobiont. Thirteen species are recognised from New Zealand, although additional taxa will doubtless be found. Previous accounts of New Zealand species include Babington [ Fl. N.Z. 2: 266-311 (1855); Hooker Handbk Fl. N.Z. 2: 550-594 (1867); Lindsay Trans. Linn. Soc. Lond. 25: 493-560 (1869); Nylander Lich. N.Z.: 31-34 (1888); Hue Nouv. Archs Mus. Hist. nat. Paris. sér. 3, 10: 213-280 (1901); Allan Tuatara 2: 15-21 (1949); Martin Tuatara 17: 106-117 (1969) and Martin and Child "Lichens of New Zealand", pp. 160-164 (1972)].

An extensive discussion of morphogenesis in Sticta and the role of photobionts in the expression of morphology is given by James and Henssen ["Lichenology: Progress and problems", pp. 27-77 (1976)]. In at least two stalked species of Sticta, (S. filix and S. lacera) the blue-green photosymbiodeme is referable to Dendriscocaulon. Hellbom [ Bihang K. Sv. Vet.-Akad. Handl. 21 (3) 13: 1-150 (1896)] in his account of New Zealand lichens places species of both Sticta and Pseudocyphellaria in Lobaria. His resulting combinations in Lobaria for species of Sticta are detailed in Zahlbruckner [ Cat. lich. univ. 3: 326-407 (1925)].