Flora of New Zealand Series

Thallus crustose, effuse, ecorticate but usually with a cartilaginous corticiform layer, not distinctly lobate. Prothallus in foliicolous species indistinct. Photobiont green, species of Chlorococcaceae, probably Trebouxia. Apothecia prominent, sessile, constricted at base, rounded, lecideine, brown-black to black, with a well-developed paraplectenchymatous excipulum. Paraphyses ± simple or richly branched, capitate, club-shaped, brown-black at apices. Asci thick-walled usually with one spore, sometimes 2-8-spored. Ascospores large, muriform or submuriform, colourless or brownish, not halonate. Pycnidia sessile, globose to cupuliform. Conidia simple, ellipsoid to flask-shaped or dumb-bell shaped.

Lopadium comprises a rather heterogeneous group of species with single-spored asci, ascospores that are muriform and not halonate, and unbranched paraphyses. It is close to Rhizocarpon. Santesson [ Symb. bot. upsal. 12: 521-525 (1972)] discusses taxonomic problems posed by the genus, but a systematic monograph is not yet available. A large proportion of species are foliicolous and others are found on soil, bark or decumbent vegetation. Ten species are recorded from New Zealand by Martin [ T.R.S.N.Z. (Bot.) 3: 139-159 (1966)] but this is an overestimate. L. ferrugineum and L. venustulum are not in the New Zealand flora. L. insidens (Stirton) Zahlbr., is referable to Clathroporina exocha and L. subamaurum (Stirton) Zahlbr., is a species of Lecidea. L. fuscoluteum is now included in Brigantiaea. Three species are recognised here.