Psora decipiens
Common name
blushing scale
Family
Psoraceae
Flora category
Lichen – Native
Endemic taxon
No
Endemic genus
No
Endemic family
No
Structural class
Lichens - Squamulose
Current conservation status
2018 | At Risk – Naturally Uncommon | Qualifiers: RR, SO, Sp
Brief description
Characteristic of limestone areas (though it is also found scattered on dry depleted soils in the Mackenzie Country on old glacial surfaces), the thick, peltate, clustered squamules with a pinkish brown upper surface, ±white-pruinose being especially characteristic. Small forms from dry soil are frequently completely white-pruinose.
Distribution
South Island: Nelson (Pelorus Bridge, Mt Arthur), Canterbury (Nape Nape, Weka Pass, Castle Hill, Flock Hill, Ashburton Gorge near Mt Somers, between Tekapo and Pukaki), Otago (Hampden), Southland (Clifden).
Known also from Great Britain, Europe, Scandinavia, Spitzbergen, Greenland, Asia, North America including Mexico, Africa and Australia.
Habitat
On limestone soils, often in drainage cracks in limestone or scattered on soils near limestone outcrops. Also colonising sandy soil in cracks between riverine rocks at Pelorus Bridge, and in part consolidating disturbed clay soil in dry grassland on moraine outwash in the Mackenzie Country, and from coastal sites (Nape Nape). An indicator of soil crusts or other substrata rich in calcium carbonate. Psora decipiens from limestone habitats associates with Fulgensia bracteata, Placynthium nigrum and Rinodina bischoffii (C. Meurk pers. comm.).
Detailed description
Thallus squamulose or minutely lobate. Squamules up to 6 mm diam., usually without a central depression; margins (especially in young squamules) usually slightly upturned, ±entire. Photobiont green, Trebouxia. Lower surface corticate, with short rhizines. Apothecia biatorine, 1-2 mm diam., brownish or black.
Chemistry: Medulla K+ yellow, C−, KC−, Pd+ yellow; containing norstictic acid.
Threats
Habitat loss and modification. Invasion by exotic weeds, particularly sward-forming grasses like Festuca rubra, is a major problem in the high fertility, low elevation sites occupied by this species.
Substrate
Terricolous (soil)
Etymology
decipiens: Deceptive
Attribution
Fact sheet prepared by Melissa A. S. Hutchison (February 2021). Brief description, Distribution, Habitat, and Features sections copied from Galloway (2007).
References and further reading
Galloway D.J. 2007: Flora of New Zealand: Lichens, including lichen-forming and lichenicolous fungi. 2nd edition. Lincoln, Manaaki Whenua Press. 2261 pp.