Pseudocyphellaria flavicans sensu Galloway
Sticta flavicans J.D. Hook. et Taylor, Hook. Lond. J. Bot. 3: 648 (1844).
Lectotype [fide Galloway and James loc. cit., p. 299 (1980)]: New Zealand. Sine loco. J.D. Hooker, BM!
Thallus orbicular to spreading, rather irregular, 5-10(-20) cm diam., ± closely attached to loosely straggling. Lobes broad, rounded, to rather ragged, imbricate centrally, contiguous to subimbricate at apices, margins crisped, variously notched or incised, isidiate. Upper surface bright green to yellow green when wet, pale yellowish-grey when dry, undulate, uneven, slightly and shallowly faveolate, shining, smooth, ± isidiate. Isidia flattened, coralloid-branched, marginal at first, then laminal, often dense. Medulla yellow. Photobiont green. Lower surface pale yellowish or creamish at margins, glabrous or minutely pubescent, darker yellow to brownish centrally. Pseudocyphellae yellow. Apothecia sparse to absent, subpedicellate, disc brown-black, matt, smooth, to 5 mm diam., concave to plane, margins pale or whitish, translucent when wet, crenulate-dentate, thalline exciple massive, white, corrugate-verrucose, obscuring disc when young, often ± short white-tomentose. Ascospores colourless, fusiform, 1-3-septate, 24-30 × 5-7 µm. Chemistry: Pulvinic acid, pulvinic dilactone, calycin, 3β,22α,-diacetoxystictane (±), 2α,3β,22α, triacetoxystictane, 2α,3β-diacetoxystictane-22-one (±), 2α,3β-diacetoxys-tictan-22-ol (±), 3β-acetoxystictane-22-ol (±), stictane-3 β,22α,-diol (±),2α -acetoxystictane-3β,22α,-diol, 3β-acetoxystictane-2α,22α,-diol, stictane-2β,3β,22α-triol (±) [Chin et al., J. chem. Soc. Perkin 1: 1437-1446 (1973)].
N: S: St: A: C: Throughout, coastal and subalpine, s.l. to 1200 m. On bark of forest trees especially Nothofagus on successional vegetation (especially Leptospermum), on rocks in humid areas in semi-shade and in subalpine grassland.
Austral
P. flavicans is characterised by the ± copious marginal isidia which impart to the lobe margins a very ragged, lacerate appearance. The massively developed white (translucent when wet), corrugate-scabrid thalline exciple ally it with P. degelii and in subalpine grass-land the two species are often sympatric, but are readily separated by the marginal flattened isidia. P. degelii has entire margins and its upper surface is often reticulate-faveolate whereas that of P. flavicans is plane to undulate. There are also chemical differences between the two species. Babington ( loc. cit., p. 275) called the species Sticta D'Urvillei (non sensu Delise) and remarked of it "... Very near the preceding (S. colensoi), and perhaps not distinct from it; and yet, after examining a considerable number of specimens of this and the preceding two species, I have seldom found much difficulty in knowing to which I should refer them; the study of these intricate plants, however, must be left to colonial botanists. The pulvinate coralline excrescences, the agreeable ochraceous hue, and especially the apothecia, distinguish S. D'Urvillei from its congeners..." An accurate coloured photograph of P. flavicans is given in Martin and Child ["Lichens of New Zealand" p. 118, pl. 30 (1972)].
