Arthonia tasmanica
Description : Thallus crustose, epi- and hypo-phloeodal, dull dingy grey, very thin, smooth to rather scurfy, forming irregular patches to 3 cm diam., less, sometimes delimited by a thin black, marginal line. Apothecia numerous, rounded, convex, black to brown-black, 0.2–0.5 mm diam., becoming slightly larger, flatter and irregular in outline with age. Epithecium reddish brown to brown, olivaceous or unchanged in K. Hymenium colourless, to 70 μm tall. Hypothecium colourless to pale-brown, 25–30 μm thick. Paraphysoids sparse, branched and anastomosing, c. 1 μm thick. Asci subglobose, 8-spored, 40–68 × 36–56 μm. Ascospores ellipsoidal to subclavate, straight or occasionally curved, hyaline, becoming grey-brown to dark-brown with age, slightly constricted across central septum, (28–)30–40 × (12–)15–18 μm.
S: Westland (Alexander Ra. Camp Creek). Amongst bryophytes on smooth bark of Wienmannia racemosa in forest (Setzepfand & Sipman 2004). Known also from Tasmania (Kantvilas & Vězda 1992; McCarthy 2003c).
Australasian
Illustration : Kantvilas & Vězda (1992: 664, fig. 2).
Arthonia tasmanica is characterised by: the corticolous habit; dull greyish, rather scurfy thallus forming irregular patches; convex, black to brown-black apothecia; and rather large, 3-septate ascospores, (28–)30–40 × (12–)15–18 μm.
