Psoroma inflatum
Family
Pannariaceae
Flora category
Lichen – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Lichens - Squamulose
Current conservation status
Not Evaluated
Brief description
The inflated, glossy thallus is characteristic for this species.
Distribution
South Island: Canterbury (Craigieburn Range), Otago (Kakanui Range, Old Man Range).
Habitat
An alpine species. Locally common on moss in rock crevices of small outcrops in subalpine scrub. Known from a handful of specimens in the Southern Alps.
Detailed description
Thallus squamulose, tripartite, terricolous, often on bryophytes and lichens, forming patches 3–10 cm wide on an indistinct hypothallus. Chlorobiont squamules 0.5‒3 mm wide, irregularly branched, forming coralloid patches of weakly ascending to erect lobes 0.3‒0.6 mm thick, without a dorsiventral morphology and anatomy; upper surface glossy, brown, glabrous, except for a distinct white tomentum on the lower, less exposed side. Cortex 60‒100 µm thick, upper part brown and sclerenchymatic, lower part pale and paraplectenchymatic, lumina mostly elongate, arranged perpendicularly to the upper surface, 4–8 × 2–4 µm, walls 3‒4 µm thick, less pigmented and thinner on the less exposed side, where lumina are more elongated, up to 12 µm long and often arranged in a labyrinth-like pattern. Chlorobiont layer 80‒150 µm thick, below the cortex, of Trebouxia cells, globose to irregularly subglobose, 8–20 µm diam.; chloroplasts angular. Medulla centrally positioned, 50‒150 µm thick, but poorly defined due to transitions towards the surrounding chlorobiont layer. Cyanobiont Nostoc, in globose to weakly coralloid, greyish cephalodia, 0.1‒0.3 mm wide, situated between chlorobiont squamules, common. Nostoc cells greyish green, irregularly subglobose to ellipsoid, often angular, with uneven surfaces, 4‒6 × 2‒3 µm, organized within small glomeruli and without visible chain structures. Apothecia common, substipitate, 3‒7 mm wide, discs reddish brown, strongly cupulate; thalline excipulum 0.3‒1 mm broad, crenate and swollen, of few and large, inrolled lobes 0.3‒1 mm wide, occasionally with inflated additional irregular outgrowths, glabrous on the lower side, except for a very thin, partial white tomentum at the bases. Epithecium brown, c. 15 µm thick; hymenium pale, 100‒120 µm, IKI+ blue; hypothecium brownish, 60‒80 µm, algal layer continuous below the hypothecium. Paraphyses simple, septate, c. 2.5 µm wide, and strongly adglutinated in the epithecium. Asci clavate, c. 80 × 15 µm, with 8 spores, internally with IKI+ blue structures, seen as tube-like in low IKI concentrations. Ascospores regularly ellipsoid to weakly citriform or ovoid, 17‒23 × 8‒11 µm, perispores 20‒30 × 10‒13 µm, regularly verrucose, apically mostly with verrucose or nodulose extensions, sometimes triangular and pointed, c. 3 µm long, rarely acuminate and c. 8 µm long. Pycnidia not observed.
Chemistry: brown melanins, lacking TLC-detectable compounds.
Similar taxa
Similar to Psoroma hypnorum, but squamules are inflated and strongly glossy, ascending, without dorsiventral morphological and anatomical structures, except for white tomentum on the less exposed side; apothecia are cupulate with large, swollen inrolled lobes of the thalline excipuli with scattered irregular outgrowths, and ascospores mostly longer and narrower.
Substrate
Terricolous
Attribution
Fact sheet prepared by Marley Ford (3 April 2021). Brief description, Distribution, Habitat, Features and Similar taxa sections copied from Elvebakk (2021).
References and further reading
Elvebakk, A. 2021: Psoroma inflatum, a new alpine lichen from New Zealand. Australasian Lichenology 89: 49-53.