Flora of New Zealand Series

≡Lecanora thiomela Nyl., Flora 48: 338 (1865).

=Buellia citrina H.Magn., Sv. Bot. Tidskr. 37: 280 (1943).

Lectotype: New Zealand. Otago, Dunedin, on basaltic rocks, W.L. Lindsay – E [fide Mayrhofer (1983: 278)]. Isolectotype – H-NYL 29088.

Buellia citrina. Holotype: New Zealand. Otago, Lake Harris Saddle, on rocks in alpine grassland, 1927, G. Einar & Greta Du Rietz – UPS.

Description : Flora (1985: 515).

Chemistry : Zeorin and a series of xanthones including thiomelin (Leuckert & Mayrhofer 1984; Elix & Portelli 1990), 8- O -methylthiomelin, 4-dechlorothiomelin, 2-dechloro-8-methylthiomelin, 4-dechloro-8- O -methylthiomelin, northiomelin, 2-dechlorothiomelin and 5,7-dichloro-2,8-dihydroxy-1,3-dimethyl-9H-xanthen-9-one (Elix et al. 1993).

N: Northland (Great Barrier I.), Auckland, Gisborne (Mt Hikurangi), to Wellington (Kapiti I., Titahi Bay, Hongoeka Bay, Mirimar Peninsula, Scorching Bay). S: Nelson (Kaihoka Lakes, Mt Benson, Cobb Valley, Mt Arthur, Cable Bay), Marlborough (Goose Bay, Whites Bay, Halfmoon Bay, Kaikoura), Canterbury (Sugarloaf, Cass, Cave Stream, Hanmer Springs, Devil's Gap, Monument Banks Peninsula, Port Hills Christchurch, Kaitorete Spit, Rangitata Valley, Mt Peel), Otago (Matukituki Valley, Harris Saddle, Routeburn Valley, The Remarkables, Old Man Ra., Poolburn, Stoneburn, Alexandra, Cromwell Gorge, Silver Peaks, Mt Charles, Otago Peninsula, Otago Heads, Maungatua, Akatore, Catlins), Southland (Howell's Point, Riverton). St: (Easy Harbour, Christmas Village, Maori Beach, Halfmoon Bay, Port Pegasus). Ch: (Owenga, Hokopai Hill). A: (Port Ross). C: Ant: ("Tilted Crag"). On coastal and upland to high-alpine rocks, s.l. to 1600 m. Also common on siliceous rocks in SE Australia and Tasmania (Mayrhofer 1984b: 527–529; McCarthy 2003c, 2006).

Australasian

Illustrations : Knight (1875a: pl. XXIII, fig. 16 – as Lecanora thiomela); Mayrhofer (1983: 268, fig. 4; 277, fig. 20).

Rinodina thiomela is characterised by: the saxicolous habit; the prominent sulphur-yellow thallus; cryptolecanorine to lecanorine apothecia with a brown-black to black disc; Pachysporaria -type ascospores with a thinly developed torus, 20–34 × 11–17 μm.; and a chemistry dominated by xanthones (see above). It is possible that more than one species is involved in this circumscription.