Lecanora kohu
Family
Lecanoraceae
Flora category
Lichen – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Lichens - Crustose
Current conservation status
2018 | Data Deficient | Qualifiers: IE, OL
Brief description
Thallus continuous, areolate, greenish white when fresh, drying cream to pale yellow; apothecia immersed, disc pale pink to pink-brown; Pd+ orange, usnic acid and zeorin absent, psoromic acid present.
Distribution
Appears to be endemic to the Chatham Islands.
Habitat
Lecanora kohu has been collected growing on exposed trunks of Chatham Island māhoe (Melicytus chathamicus), matipo (Myrsine chathamica), hikoa karamu (Coprosma chathamica), akeake (Olearia traversiorum), and tarahinau (Dracophyllum arboreum), and on the exposed, mature branches of a widespread, common unnamed species of Muehlenbeckia (M. aff. australis). Associated lichens were typically sparse: on Muehlenbeckia, only Opegrapha agelaeoides was noted, whilst on Melicytus chathamicus, L. kohu grew in association with Bacidia laurocerasi, Phlyctis sordida and P. uncinata.
Detailed description
Thallus crustose, areolate-cracked, greenish-white when fresh, drying to cream to pale-yellow, soredia and isidia absent. Areoles rounded to oblong with irregular-crenate margins, 0.25–0.5 mm in length or diameter, plane to slightly concave, cream to yellow-grey in colour, smooth to slightly roughened between areoles. Photobiont trebouxioid, individual cells 5–10 μm in diameter. Apothecia 0.25–0.4 mm in diameter, immersed, flat to slightly concave, single to grouped, 1–3(–5) per areole, but several areoles merge and apothecia become clustered, disc pale pink to pink-brown, matt, epruinose. Thalline margin generally not apparent, but discs are generally embedded in thalline tissue. Parathecium white to cream, scarcely evident in young apothecia, level with disc and inconspicuous in older apothecia, in section 22–62.5 μm wide and 30–65 μm tall, consisting of gelatinised hyphae, colourless to pale straw-coloured, IKI–, HNO3−, POL+ crystals common, algae occasionally present at base. Hypothecium 37.5–87.5 μm tall, colourless or pale-straw-coloured, small oil droplets sometimes present. Hymenium 35–60 μm tall, colourless, IKI+ bright blue, HNO3−; epihymenium brown, granular, POL+, 5–10(–25) μm thick; paraphyses colourless, simple or occasionally branched, with lumina 0.7–1.0 μm wide, apically not thickened. Asci Lecanora-type, 32.5–45 × 9–15 μm. Ascospores 8 per ascus, colourless, simple, ellipsoid, 9–12.5 × 5–7 μm; pycnidia not seen.
Chemistry: Thallus K+ (very weak) yellow, C– Pd+ yellow; atranorin and psoromic acid by TLC.
Similar taxa
Lecanora kohu is morphologically similar to Lecanora symmicta (Ach.) Ach., from which it is distinguished by the continuous, areolate thallus, immersed apothecia with pale pink to pink-brown discs, and by the presence of atranorin and psoromic acid rather than usnic acid, zeorin and xanthones in the thallus.
Substrate
Corticolous
Etymology
kohu: The epithet ‘kohu’ derives from Te Reo Māori for ‘mist’ (K.A. Raharaha, Ngati Kuri, pers. comm., 22 March 2017). The name alludes to the sea fog that often shrouds the location in which this species was found, Rangatira (South East Island), the southern-most of the main islands of the Chatham Islands group.
Attribution
Fact sheet prepared by Melissa Hutchison (5 July 2021). Brief description, Distribution, Habitat, Features and Similar taxa sections sourced from Printzen et al. (2017).
References and further reading
Printzen C., Blanchon D.J., Fryday A.M., de Lange P.J., Houston D. M. and Rolfe J.R. 2017: Lecanora kohu, a new species of Lecanora (lichenised Ascomycota: Lecanoraceae) from the Chatham Islands, New Zealand. New Zealand Journal of Botany 55(4): 439-451.