Flora of New Zealand Series

≡Baeomyces arcuatus Stirt., Bot. J. Linn. Soc. 14: 460 (1875).

=Baeomyces subgranosus Stirt., Bot. J. Linn. Soc. 14: 460 (1875).

=Baeomyces fungoides New Zealand records. 

Baeomyces arcuatus. Lectotype: New Zealand. Near Wellington, J.Buchanan 28/74 – BM [fide Galloway (1980a: 79)].

Baeomyces subgranosus. Lectotype: New Zealand. Wellington, Tinakori Hills, viii.1873, J.Buchanan 180 – WELT [fide Galloway (1980a: 79)].

Descriptions : Flora (1985: 37 – as Baeomyces fungoides); Johnston (2001b: 19).

Chemistry : Thallus and soralia 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.

N: Northland (Maungataniwha Ra., Kawerua, Puketi Forest, Cavalli Is, Ririwha I., Bay of Islands, Tutukaka, Great Barrier I.), South Auckland (Hunua Ra., Mt Maungatawhiri, Coromandel Peninsula, Cuvier I., Slipper I.) to Wellington (Volcanic Plateau, Tinakori Hill). S: Nelson (Cobb Valley, St Arnaud Ra.), Marlborough (Mt Stokes, Resolution Bay), Westland (Harihari), Canterbury (Arthur's Pass, Banks Peninsula, Mt Peel), Otago (Lake Onslow, Flagstaff), Southland (Fiordland to the Awarua Plains). St: (Oban to Port Pegasus). Characteristically on clay, often alongside paths and often very common on vehicle tracks in grassland, and a common component in the succession leading to revegetation of clay banks, often also on bare soil in lawns – rarely on rock, bark or litter, s.l. to 1000 m. Colonies on clay in subalpine grassland in Central Otago appear to grow rapidly during winter months. Known also from Australia (Gierl & Kalb 1993; Johnston 2001b: 20; McCarthy 2003c, 2006). Earlier accounts (Galloway 1980a, 1985a, 1992d) referred this species to the neotropical species Baeomyces fungoides (=Dibaeis fungoides).

Australasian

Exsiccati : Vězda (1997c: No. 281).

Illustrations : Martin & Child (1972: 43, pl. 2 – as Baeomyces fungoides); Galloway (1980a: 79, fig. 2 – as Baeomyces subgranosus); Gierl & Kalb (1993: 604, fig. 23); Malcolm & Galloway (1997: 98, 115); Malcolm & Malcolm (2000: 18, 77); Flora of Australia58A (2001: xiv, pl. 13).

Dibaeis arcuata is characterised by: the terricolous habit; a crustose, scurfy, grey-white to white thallus, with or without scattered, efflorescent white soralia; a stalked simple podetium (to 2 cm tall), with terminal, globose, capitate or convolute, pale-pink to orange-pink apothecia; fusiform, ascospores, 12–30 × 2–4 μm; and a chemistry containing baeomycesic and squamatic acids (±barbatic acid). A beautiful lichen!