Flora of New Zealand Series

P. episticta (Nyl.) Vainio, Philipp. J. Sci. Sect. C. 8: 117 (1913).

Sticta episticta Nyl., J. Linn. Soc. Lond. Bot. 9: 248 (1866).

Lectotype (fide Galloway and James loc. cit., p. 298): New Zealand. Otago, Dunedin, on trunks of trees. W.L. Lindsay E!

Thallus orbicular to spreading, loosely to closely attached, rather ragged, 8-12(-20) cm diam. Lobes ± linear-elongate, or sometimes rounded, margins deeply indented, ragged, isidiate-lobulate, often ascending, rather fragile. Upper surface bright lettuce-green when wet, pale greyish-green to pale fawn when dry, smooth, undulate to ± wrinkled, matt or shining, with numerous, white, minute, punctiform pseudocyphellae, isidiate, without soredia or maculae. Isidia delicate, flattened, coralloid-branched, rarely ± terete, finger-like, marginal at first then laminal. Medulla white. Photobiont green. Lower surface pale buff to whitish and glabrous at apices, ± uniformly brown-tomentose in older parts. Pseudocyphellae white, scattered, sparse to numerous, sunk in tomentum, to 1 mm diam. Apothecia rare, scattered, subpedicellate, disc dark redbrown, matt, epruinose, concave to plane, to 2 mm diam., margins pale, corrugate-scabrid at first, crenate-coronate with age, exciple massive, pale flesh-coloured, corrugate-scabrid. Ascospores colourless to pale yellowish, oblong-fusiform, 1-3-septate, 30 × 7 µm. Chemistry: Two chemodemes present. (i): 7β-acetoxyhopan-22-ol, hopane-15α, 22-diol, and two unidentified compounds. (ii): 15α-acetoxy-22-hydroxyhopan-24-oic acid, 15α-22-dihydroxy-24-hopanoic acid. (Dr A.L. Wilkins pers. comm.).

N: S: St: Throughout, mainly lowland and coastal in damp, humid, semi-shaded habitats in both forest and successional vegetation, s.l. to 800 m.

Endemic

P. episticta is distinguished from P. lividofusca by the more fragile, narrow, laciniate lobes with lacerate, isidiate margins. P. psilophylla (see below) occasionally has superficial pseudocyphellae but these result from fractured isidia, and this latter species is readily distinguished from P. episticta by its pinkish-buff, glabrous lower surface.