Flora of New Zealand Series

≡Chiodecton subdiscordans Nyl., Flora 62: 221 (1879).

=Byssoloma rotuliforme (Müll.Arg.) R.Sant in C.A. Thorold, J. Ecol 40: 129 (1952).

≡Patellaria rotuliformis Müll.Arg., Flora 64: 228 (1881).

Description : Flora (1985: 53 – as Byssoloma rotuliforme).

Chemistry : Characterised by the presence of the 2,5,7-trichloro-3- O- methylnorlichexanthone chemosyndrome including: vinetorin (tr.), 5,7-dichloro-3- O- methylnorlichexanthone (major), 4- O- methylasemone (minor), 3- O -methylthiophanic acid (tr.), 2,5,7-trichloro-3- O- methylnorlichexanthone (major) and, 5,7-dichloro-6- O- methylnorlichexanthone (minor) (Elix et al. 1995a: 85–86).

N: Auckland (Waitakere Ra.), South Auckland (Hunua Ra.), Wellington (Kitchener Park, Feilding). S: Westland (NW of Lake Kanieri). On leaves of Beilschmiedia tawa, Podocarpus totara, Pseudopanax crassifolius and Pseudowintera colorata. Widely distributed in tropical and subtropical regions (Kantvilas & Jarman 1993; Kantvilas et al. 1994; Lücking & Kalb 2001; Aptroot 2002e; Lücking et al. 2003; McCarthy 2003c, 2006). Known also from the west of Ireland and in Central and Southern Europe (James 1971; Sérusiaux 1992; Nimis & Martellos 2003) where it colonises damp rocks and twigs and stems of Calluna, and recently recorded from British Columbia (Aptroot 1996: 196) and Réunion (Rønhede et al. 2003).

Pantropical

Illustrations : Lücking (1992a: 140, fig. 51E; 1995a: 68, fig. 2C); Malcolm & Galloway (1997: 96, 157); Australasian Lichenology 45 (1999: back cover); Malcolm & Malcolm (2000: 109; 2001: 4, 38).

Byssoloma subdiscordans is characterised by: the foliicolous habit; the whitish to whitish green, warty thallus; black apothecial discs with white, byssoid margins; and 3-septate ascospores, 10–17 × 3–5 μm.