


Australian Biological Resources Study
| Checklist of the Lichens of Australia and its Island Territories | ||
| Introduction | A–D | E–O | P–R | S–Z | Oceanic Islands | References | ||
| Melanotrema platystomum (Mont.) Frisch | ||
| in A.Frisch, K.Kalb & M.Grube, Biblioth. Lichenol. 92: 397 (2006) Thelotrema platystomum Mont., Ann. Sci. Nat., Bot., sér. 2, 19: 79 (1843); — Ocellularia platystoma (Mont.) Zahlbr., Cat. Lich. Univ. 2: 598 (1923). T: French Guiana, F.M.R.Leprieur 491; iso: H-NYL 22795. | ||
| Thallus endophloeodal, to c. 100 µm thick, pale  grey to yellowish grey, dull, occasionally smooth, usually rough and porous,  continuous, usually non-rimose. Cortex and protocortex absent. Algal layer  poorly developed, ±discontinuous; calcium oxalate crystals sparse, small and  scattered. Vegetative propagules not seen. Ascomata conspicuous, to c. 1.5 mm diam.,  ±rounded, apothecioid, solitary or marginally fused, mostly immersed,  occasionally moderately prominent and hemispherical. Disc with the columella  visible in mature ascomata, epruinose to slightly pruinose, rather dark grey,  free, entire. Pores moderately broad, to c. 0.6 mm diam., ±rounded to slightly  irregular, entire; apex of proper exciple becoming visible from above, free,  epruinose, greyish, rather short, slightly incurved to erect. Thalline rim  margin broad to gaping, ±rounded to slightly irregular, moderately thin, entire  to slightly split or eroded, concolorous with the thallus or becoming dark grey;  thalline rim incurved. Proper exciple free, moderately thin to rather thick  towards the upper parts, brownish internally to dark brown, or distinctly carbonised  marginally and in the upper parts, occasionally amyloid at the base. Hymenium to  c. 120 µm thick, not inspersed, moderately conglutinated; paraphyses ±bent,  unbranched, with unthickened tips; columellar structures well-developed, to 0.6  mm wide, replacing most of the hymenium, entire, completely carbonised, largely  uncovered. Epihymenium hyaline, with greyish or brownish granules. Asci  8-spored; tholus initially thick, becoming thin. Ascospores transversely  septate, oblong to fusiform or clavate, with ±rounded to subacute or apiculate  ends, hyaline, distinctly amyloid, 12–25 × 5–7 µm, with 4–8 locules; locules ±rounded  to angular, ±lentiform to oblong or rectangular, with hemispherical to conical  end cells; septa moderately thin, regular to slightly irregular; ascospore wall  and endospore moderately thick, non-halonate. Pycnidia  not seen; according to Frisch et al. (2006) immersed in the thallus or in verrucae, with a brownish pore area; conidia  bacilliform, to c. 8 × 1 µm. CHEMISTRY: Thallus K–, C–, P–; no secondary compounds detectable by TLC. | ||
| Common in lowland rainforest in north-eastern Qld. This pantropical species is reported for the first time from Australia. | ||
| Mangold et al. (2009) | ||
| Checklist Index | 
| Introduction | A–D | E–O | P–R | S–Z | Oceanic Islands | References | 
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