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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
Myriotrema viridialbum (Kremp.) Hale

Mycotaxon 11: 135 (1980)

Thelotrema viridialbum Kremp., Flora 49: 221 (1876); — Ocellularia viridialba (Kremp.) Müll.Arg., Flora 70: 398 (1887); — Rhabdodiscus viridialbus (Kremp.) Vain., Ann. Acad. Sci. Fenn., ser. A, 15(6): 184 (1921).

T: Rio de Janeiro, Brazil, A.Glaziou 3193; lecto: M, fide M.E.Hale (in herb.); isolecto: C.

  Thallus usually epiphloeodal, to c. 700 µm thick, pale yellowish to greenish grey or olive, dull to glossy, smooth, continuous to rugose, rarely verrucose, usually rimose. True cortex ±continuous, yellowish, to c. 50 µm thick, consisting of periclinal hyphae. Algal layer well developed, continuous; calcium oxalate crystals absent or sparse, then large and clustered; medulla distinct. Vegetative propagules not seen. Ascomata to c. (0.5–) 0.8 mm diam., mostly ±rounded, apothecioid, occasionally solitary but often fused, immersed to ±emergent in older ascomata, then hemispherical to urceolate. Disc occasionally becoming partly visible from above, pale flesh-coloured, pruinose. Pores small to gaping, to c. (0.3–) 0.6 mm diam., ±rounded, entire to slightly split; proper exciple often becoming apically or completely visible from above, off-white, sometimes slightly shrunken, incurved. Thalline rim margin becoming moderately wide to gaping, ±rounded, thick, predominantly ±entire, whitish or brighter than the thallus; thalline rim incurved. Proper exciple fused to partly or entirely free, thick to thin, with or without a thin hyaline area internally, completely or marginally greyish, sometimes faintly amyloid. Hymenium to c. 160 µm thick, not inspersed, occasionally with large ±columnar aggregates of bacilliform crystals (soluble in K), strongly conglutinated; paraphyses thick, irregular, often distinctly septate, ±interwoven, with thickened irregular tips; lateral paraphyses and true columella absent; columella-like structures sometimes present in fused ascomata. Epihymenium hyaline, with greyish granules. Asci 8-spored; tholus thin to thick. Ascospores submuriform, subglobose to ellipsoidal or somewhat clavate, with ±rounded to subacute ends, rarely acute, hyaline, strongly amyloid, 10–20 × 5–12 µm, with 3–6 × 1–2 (–3) locules; locules ±rounded, subglobose to lentiform; end cells the same shape, hemispherical or conical; septa thick, often irregular; ascospore wall thick, often thinly halonate; endospore thick. Pycnidia immersed or in distinct thallus warts, with a brownish pore area surrounded by a bright ±eroded ring. Conidia fusiform, to c. 6 × 1 µm.
CHEMISTRY: Thallus K–, C–, P–, UV±; containing hypoprotocetraric acid (major), 4-O-demethylnotatic acid (minor to trace), convirensic acid (minor to trace), conhypoproto-cetraric acid (minor to trace), conprotocetraric acid (trace), ±lichexanthone.
  Rare on bark in rainforest in north-eastern Qld, at altitudes of 600–1100 m. Previously known from the Neotropics.  
  Mangold et al. (2009)  

Checklist Index
Introduction | A–D | E–O | P–R | S–Z | Oceanic Islands | References

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