Flora of New Zealand Series

P. coriacea (J.D. Hook. et Taylor) D. Galloway et P. James, Lichenologist 12: 295 (1980).

Sticta coriacea J.D. Hook. et Taylor, Hook. Lond. J. Bot. 3: 648 (1844).

Lectotype [fide Galloway and James loc. cit., p. 295 (1980)]: New Zealand. Sine loco, W. Colenso 3754, BM!

Thallus orbicular to spreading, 5-10(-25) cm diam., loosely to closely attached. Lobes linear-elongate, ± subdichotomously branching, discrete, or ± imbricate, to broad and rounded, ± continuous centrally, margins entire, sinuous, subascendent, thickened below, conspicuously white-pubescent or tomentose, rather tough, coriaceous in texture. Upper surface bright lettuce-green when wet, pale greyish-green or fawnish when dry, becoming brown, buff or yellowish on storage, smooth, matt, sometimes ± scabrid-areolate in patches, and with a thin, scattered pubescence especially at margins, without soredia, isidia, phyllidia or pseudocyphellae. Internal cephalodia often visible as small, hemispherical swellings on upper and lower surface. Medulla white. Photobiont green. Lower surface pale buff to dark chocolate-brown, densely tomentose, tomentum white, silky, rather soft. Pseudocyphellae white, conspicuous, large, numerous, often with a raised margin at centre, immarginate towards lobe apices and margins. Apothecia sparse to frequent, laminal and marginal, sessile to subpedicellate, 1-4 mm diam., disc red-brown, matt, smooth, epruinose, concave to plane, margins entire or crenulate, massive at first and obscuring disc, excluded with age, ± white-pubescent or tomentose, thalline exciple areolate-scabrid, often white-pubescent. Ascospores brown, 1-3-septate, fusiform, 23-33 × 7-11 µm. Chemistry: 7β-acetoxyhopan-22-ol, hopane-15α,22-diol and hopane-7β,22-diol (tr.).

N: S: St: Throughout south of lat. 35° 45' S. Mainly lowland on successional vegetation (especially Leptospermum) and on trees (especially in Nothofagus forest) at forest margins. A species of open situations but tolerates moderate shade. In Fiordland, specimens often reach great size.

Endemic

P. coriacea is one of a small group of endemic species characterised by lobes with a white marginal pubescence. The lower surface is characteristically densely felted-tomentose, chocolate-brown and with large, white, prominent pseudocyphellae, often abruptly margined and superficially resembling cyphellae. It is distinguished from P. fimbriata by the entire margins which are never phyllidiate and from P. allanii by the presence of a green photobiont. On Myrsine australis bark on the northern slopes of Mt Peel P. coriacea forms photosymbiodeme associations with P. allanii (see under the latter species). An excellent plate drawn by Walter Fitch is given in Babington ( loc. cit., pl. CXXV A) where details of the marginal pubescence and the apothecia and spores are clearly shown. A coloured photograph of the species (as Sticta subcoriacea) is given in Martin and Child ["Lichens of New Zealand", p. 121, pl. 33 (1972)].