Psoroma melanizum
Family
Pannariaceae
Flora category
Lichen – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Lichens - Crustose
Current conservation status
2018 | Not Threatened
Brief description
Characterised by the saxicolous habit; the squamulose thallus, closely attached in compact rosettes and often mosaic-forming, 1–3 cm diam., bordered by a thin, black, byssoid prothallus, 1–2 mm wide; the thalline squamules are minute, 0.2–1.0 mm diam., yellowish brown to pale or whitish at margins, often secondarily lobulate and dispersed at margins, coalescent centrally forming a diffract-areolate crust; the scattered cephalodia, marginal on squamules, wrinkled-plicate; the frequent, sessile, predominantly central apothecia, 0.5–1.5 mm diam., the disc brown-black, plane to subconcave, with thin, crenulate margins concolorous with thallus; and subglobose to globose ascospores, 10–15(–16.5) μm diam., with oily-granular contents and a perispore 1–3 μm thick.
Distribution
South Island: Nelson (Brook Stream), Marlborough (above Ship Cove), Canterbury (Dyer’s Pass, Banks Peninsula), Otago (Trotter’s Gorge, Mount Watkin, Silver Peaks, Hammond’s Hill Merton, Boyd’s Bush N Taieri, Dunedin, Goat Island Otago Harbour, Akatore, Tautuku Bay), Southland (Doubtful Sound, Supper Cove Dusky Sound). Stewart Island: (Noble Island, Port Pegasus). Auckland Islands.
Habitat
On coastal rocks above Verrucaria zone, and on rocks in damp, humid sites in coastal and lowland forest, s.l. to 400 m. It associates with Dirina neozelandica, Opegrapha diaphoriza, Pertusaria graphica, Placopsis cribellans and Tylothallia pahiensis on exposed rocky shore habitats, while in humid, shaded sites, it associates with species of Leptogium, Pannaria leproloma, P. minutiphylla and Psoromidium aleuroides.
Detailed description
Thallus squamulose, closely attached, in compact rosettes, often confluent in mosaics, 1-3 cm diam., bordered by a short, black, byssoid prothallus, 1-2 mm wide. Squamules minute, 0.2-1.0 mm diam., round to irregular, concave to plane to subconvex, margins entire, slightly thickened, often secondarily lobulate and dispersed at margins, coalescing, imbricate centrally, forming a diffract-areolate crust, prothallus visible between areolae, yellowish to pale whitish at margins, whole thallus superficially blackened, smooth to coriaceous, shining, waxy, epruinose. Cephalodia frequent, scattered, marginal on squamules, occasionally laminal or on hyphae of prothallus, ± rosette-shaped, dark purplish-grey, rising above squamules, wrinkled-plicate, smooth to slightly granular. Apothecia sessile, frequent centrally, rarely marginal, round to irregular, 0.5-1.5 mm diam., disc brown-black, plane to subconcave, matt, epruinose, margins thin, pale or concolorous with thallus, crenulate. Ascospores ellipsoid to subglobose, 12 µm diam., or smaller, 4-6 × 3 µm.
Substrate
Saxicolous
Attribution
Fact sheet prepared by Marley Ford (25 August 2021). Brief description, Distribution, Habitat, and Features sections copied from Galloway (1985; 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.