Flora of New Zealand Series

Lectotype: New Zealand. Auckland, Rangitoto I., on trunk of Avicennia officinalis in salt lagoon, viii.1933, H.H. Allan 46 – W [fide D.J. Galloway in Archer & Elix (1994a: 211)]. Isolectotype – CHR 374706.

Description : Thallus pale yellowish fawn, conspicuously areolate, surface smooth and dull, without isidia or soredia. Apothecia in pore-like verrucae, numerous, conspicuous, often confluent, flattened-hemispherical to immersed, 0.5–1 mm diam.; ostioles conspicuous, black, 1 per verruca, 0.1–0.4 mm diam., sometimes with a pale-grey translucent margin. Ascospores 2 per ascus (rarely 3), ellipsoidal, smooth (70–)85–110(–132) × 35–45 μm.

Chemistry : K−, KC+ weak yellow, C−, Pd−; containing thiophaninic acid (major) with 2-chloro-6- O -methylnorlichexanthone (tr.) and 4-chloro-6- O -methylnorlichexanthone (tr.) (Archer & Elix 1994a: 211).

N: Northland (Waitiki Stream, Paihia), Auckland (Rangitoto I.). S: Marlborough (Resolution Bay). On coastal shrubs, especially mangroves (Avicennia marina) in northern localities; on Corynocarpus laevigatus and Melicytus ramiflorus in the Sounds locality.

Endemic

Pertusaria alboatra is characterised by: the corticolous habit; verruciform apothecia with black ostioles; 2-spored (rarely 3-spored) asci; and thiophaninic acid in the medulla. P. melaleucoides is similar but lacks thiophaninic acid and never has 3-spored asci.