Fuscoderma applanatum
≡Leioderma applanatum D.J.Galloway & P.M.Jørg., Lichenologist 19 (4): 371 (1987).
Holotype: New Zealand. South I., Canterbury, Nina Valley, on Nothofagus solandri var. cliffortioides, 11.ix.1981, P.W. James & P.M. Jørgensen 8557 – BM. Isotypes – BG, CHR.
Description : Thallus squamulose–subfoliose, becoming ±orbicular in loosely attached, flat rosettes, 1–4(–5) cm diam. Lobes convex, 0.5–2 mm wide, discrete to imbricate. Margins thickened, often ±curled under, entire or incised, distinctly short-pubescent to pruinose, pubescence occasionally spreading to lamina. Upper surface dark greyish or glaucous–olivaceous when wet, olive to chestnut greyish when dry, occasionally shallowly pitted or areolate–scabrid. Lower surface white at margins, buff to dark-brown centrally, uniformly arachnoid–tomentose. Rhizohyphae 0.2–1 mm long, whitish buff to black, often tufted at apices. Apothecia common, often abundant, sessile, constricted at base, laminal to submarginal, discrete to crowded (3–6-together), rounded or slightly distorted through mutual pressure, 0.1–1(–1.2) mm diam., visible at first as pale swellings on the upper surface, when emergent shallowly concave with a prominent, pale proper exciple, becoming plane to subconvex; disc matt, pale orange-brown, proper exciple persistent, translucent when wet, paler than disc when dry, most obvious in young fruits, thinner and occasionally excluded at maturity. Hymenium 90–110 μm tall. Ascospores 10–16 × 5–7 μm, apiculate at both ends, apiculae 18–22 μm long. Pycnidia very rare, on lobe margins, minute, 0.1 mm diam., swollen, papillate, solitary or aggregated, red-brown to black.
N: South Auckland (Hunua Ra., Kaimanawa Ra.) to Wellington. S: Nelson to Canterbury (Hawdon River), Otago (Routeburn), Southland (Lake Thomson, Lake Monowai Fiordland), 350–750 m. A corticolous species growing both on exposed bark and over mosses on trunks of forest trees or branches of shrubs in damp, rather shaded habitats. It is most common in areas of high humidity especially on Nothofagus bark. Also known from Dracophyllum, Knightia excelsa, Metrosideros, Phyllocladus trichomanoides, Podocarpus hallii and Weinmannia racemosa. It has a rather more restricted range than F. amphibolum.
Endemic
Illustrations : Galloway & Jørgensen (1987: 372, fig. 17; 373, fig. 18); Jørgensen & Sipman (2002a: 35, fig. 2).
Fuscoderma applanatum is closely related to F. amphibolum but is distinguished from it by the thicker, olive to chestnut-grey thallus, the abundant presence of apothecia, and the absence of soredia.
