Maronea constans
Family
Fuscideaceae
Flora category
Lichen – Native
Endemic taxon
No
Endemic genus
No
Endemic family
No
Structural class
Lichens - Crustose
Current conservation status
2018 | At Risk – Naturally Uncommon | Qualifiers: DP, SO
Brief description
Characterised by the corticolous habit; the neat, rosette-forming crustose thallus; red-brown apothecial discs with pale margins; a brown epithecium reacting K+ violet-brown; a hyaline hymenium 60–100 μm tall, inspersed with oil droplets; a colourless hypothecium inspersed with oil droplets; and polysporous asci (walls I+ blue) containing 80–100 ascospores.
Distribution
South Island: Canterbury (Canterbury Plains), Otago (Dunedin).
Probably more widespread than records show and possibly often mistaken for a species of Lecanora or for Caloplaca homologa (q.v.).
Known also from Europe where it is apparently declining, in Sweden where it is rare or even extinct, in North America, India, Ecuador; Thailand, Australia and Tasmania.
Habitat
On bark of Magnolia, Quercus, Sorbus etc., on wayside trees and in parks and gardens.
Detailed description
Thallus closely attached, pale green-grey to brownish, granular, orbicular, in ±neat rosettes or spreading, 1–3 cm diam., corticolous. Apothecia sessile, to 1.5 mm diam., rounded, ±central, disc red-brown to dull-black, matt, epruinose, margins crenulate, concolorous with thallus or paler. Epithecium brown, 10–15 μm thick, K+ violet-brown. Hymenium colourless, 60–80(–90) μm tall, inspersed with oil droplets, I−. Hypothecium colourless, 30–75 μm thick. Asci I+ blue, 40–60 × 9–15 μm containing 80–100 spores. Ascospores colourless, simple to 1-septate, 3–6(–8) × 2.5–3 μm.
Chemistry: Thallus K−, C−. KC−, Pd−; containing sekikaic acid with traces of homosekikaic acid and 4’-O-demethylsekikaic acid.
Substrate
Corticolous
Maronea is a cosmopolitan genus of 13 species included in the family Fuscideaceae. One species occurs in New Zealand and is found on the bark of introduced trees in urban and rural areas.
Attribution
Fact sheet prepared by Melissa Hutchison (25 August 2021). Brief description, Distribution, Habitat, and Features sections copied from Galloway (1985, 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.