Flora of New Zealand Series

≡Baeomyces absolutus Tuck., Am. J. Arts Sci. ser. 2, 28: 201 (1859).

=Baeomyces novae-zelandiae C.Knight, Trans. N. Z. Inst. 15: 348 (1883).

≡Baeomyces absolutus var. novae-zelandiae (C.Knight) Zahlbr., Cat. lich. univ. 4 (3): 408 (1926).

Baeomyces novaezelandiae. Lectotype: New Zealand. Sine loco [probably Wellington], Charles Knight – WELT [fide Galloway (1980a: 80)].

Description : Flora (1985: 36–37 – as Baeomyces absolutus). See also Johnston (2001b: 18–19) and Ryan & Kalb (2002: 169).

Chemistry : Thallus K− or + pale yellow, UV+ white; apothecia K+ yellow, Pd+ yellow-orange; containing baeomycesic (major), squamatic (UV+ white, tr.), consquamatic (tr.), barbatic (±) and ursolic (tr.) acids (Johnston 2001b: 19).

N: Northland (Whangarei, Little Barrier I., Tokatoka), South Auckland (Te Aroha) to Wellington (Tararua Ra.). S: Nelson to Fiordland. St: (Mt Anglem). On rock in alpine habitats and in forest, also on clay soils alongside paths and tracks in forest, in moist humid habitats, s.l. to 1000 m. Known also from North, Central and South America, Japan, the Philippines, New Guinea and Australia (Galloway 1980a; Gierl & Kalb 1993; Johnston 2001b: 19; Aptroot 2002e; Ryan & Kalb 2002: 169; McCarthy 2003c, 2006).

Pantropical

Exsiccati : Vězda (1997h: No. 334).

Illustrations : Knight (1883: pl. XXXVIII, fig. 28 – as Baeomyces novae-zelandiae); Gierl & Kalb (1993: 602, fig. 13; 604, fig. 18).

Dibaeis absoluta is characterised by: the saxicolous habit; the emerald-green to lime-green, minutely granular to varnish-like, crustose thallus; pale pink, sessile apothecia, the disc minutely wrinkled–scabrid, ±white-pruinose; uniseriate, oblong ellipsoidal, colourless, simple ascospores 7–15 × 4–5 μm; and baeomycesic, squamatic and ±barbatic acids as secondary compounds. It is distinguished from the superficially similar Icmadophila ericetorum that has 1-septate ascospores, and a thallus reacting K+ orange (thamnolic and perlatolic acids) and by habitat preference. Icmadophila ericetorum grows on peaty soils and on plant debris, whereas Dibaeis absoluta occurs on rocks, rarely on clay or sandy soil. According to Rambold et al. (1993: 231) "Dibaeis subg. Apoda shows a relatively basal set of characters: the turbinate shape of the ascocarps, the mostly non-lichenised stipes, the poorly developed thallus horizontalis, in combination with asci showing only weak tendencies of reduction of the amyloid ring, and the simple, ellipsoidal spores. With regard to ascocarp and ascospore shapes, Dibaeis subg. Apoda may have close affinities with Icmadophila and Knightiella".