Psoroma caliginosum
Family
Pannariaceae
Flora category
Lichen – Native
Endemic taxon
No
Endemic genus
No
Endemic family
No
Structural class
Lichens - Squamulose
Current conservation status
2018 | Not Threatened | Qualifiers: SO
Brief description
Characterised by the corticolous (occasionally foliicolous) habit; the squamulose thallus developed on a black, minutely fibrous prothallus, sometimes extending 2–4 mm beyond marginal squamules; thalline squamules closely appressed, flattened, smooth, lobate-crenate, the margins whitish pubescent and appearing “frosted”; the large, placodioid cephalodia, to 3 mm diam., laminal or marginal on squamules or developing directly on prothallus; the ±central apothecia, with thick, inrolled, crenate-striate margins, and a matt, plane, dark-brown to black disc often obliterated by concentric rings of thalline tissue or with small thalline lobules; and large ascospores, (12–)17–24 × (9–)12–14 μm.
Distribution
North Island: Northland (Tahurangi Bluff), Taranaki (Mt Taranaki), Wellington (Wellington). South Island: Nelson (Mt Robert) Stewart Island: (Port Pegasus). Chatham Islands. Auckland Island. Campbell Island.
Known also from East Australia and Tasmania.
Habitat
Throughout, widely distributed in mainly lowland and coastal habitats, s.l. to 1500 m, on trees and shrubs, rarely on rocks in damp, shaded habitats.
Detailed description
Thallus squamulose, very closely attached to substrate, in ± rounded or closely spreading patches, 2-10 cm diam., on a fine, black, minutely fibrous, closely attached prothallus which may extend 2-4 mm beyond margins of squamules. Squamules very closely appressed, flattened, smooth, lobate-crenate, rounded and scattered at margins, becoming rosette-shaped 1-2 mm wide, coalescing into a closely attached, ± imbricate mosaic centrally, apices and margins of squamules slightly thickened, ± whitish pubescent, pubescence very short, minute, appearing “frosted”, pale greenish, yellow-green to brownish or pale glaucous, matt or ± shining, paler at margins, glossy, smooth. Cephalodia large, lobate-crenate, to 3 mm diam., flattened, placodioid, smooth to ridged-striate, pale blue-grey or blackened to bluish-brown, ± frequent at margins, laminal or marginal on squamules or growing directly on hyphae of prothallus, often concolorous with thallus when dry, with a faint blue-black cast. Apothecia sessile, closely attached to squamules or projecting above, ± central, sparse to numerous, round to irregular, 0.2-1.0 mm diam., margins thick, inrolled, striate-crenate, concolorous with thallus, disc matt, plane, dark brown or black, occasionally with small thalline lobules centrally or disc ± obliterated by concentric rings of thalline tissue, epruinose. Ascospores large, (12-)17-24 × (9-)12-14 µm.
Chemistry: TLC−, all reactions negative.
Substrate
Corticolous
Attribution
Fact sheet prepared by Marley Ford (29 January 2024). Brief description, Distribution, Habitat, and Features sections copied from Galloway (1985) & Galloway (2007).
References and further reading
Galloway D.J. 1985: Flora of New Zealand: Lichens. Wellington: PD Hasselberg, Government Printer. 662 pp.
Galloway D.J. 2007: Flora of New Zealand: Lichens, including lichen-forming and lichenicolous fungi. 2nd edition. Lincoln, Manaaki Whenua Press. 2261 pp.