Bacidia placodioides
Family
Ramalinaceae
Flora category
Lichen – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Lichens - Placodioid
Current conservation status
2018 | Data Deficient | Qualifiers: OL
Distribution
Campbell Island.
Habitat
Known only from Campbell Island, where it grows on both calcareous and non-calcareous, sea-shore rocks.
Associated taxa include species of Caloplaca, Collemopsidium and Verrucaria, suggesting that it grows in the mesic-supralittoral or lower Xeric-supralittoral zones. Other collections from the same localities include Caloplaca regalis, Dirina reozelandica, Lecanora capistrata, Lecidea lygomma, Pertusaria erubescens, P. graphica, Teplomela atra, Turgidosculum complicatulum, Verrucaria mucosa.
Detailed description
Thallus areolate and usually placodioid, circular, 0.7–2 cm diam., or becoming confluent; areoles convex to bullate, 0.3-1 mm wide, but radially elongate at the thallus margin, forming convex lobes 0.25-1.4 mm long, greyish white or with a faint yellow-green tinge, matt; lobe tips sometimes slightly raised from the surface of the substratum, but ecorticate below; prothallus absent. In section: 200-300 microns thick or to 420 microns (or more) in old, bullate areoles; hyphae (2-)3(-3.5) um wide, predominantly vertically orientated, cortex (phenocortex) 15-35 um thick, hyaline; algal layer 60% 110 pm thick: medulla 1. Photobiont cells 5-10 um diam. Apothecia at first plane and marginate, 0.3 0.5 mm diam., but later becoming convex with a reflexed margin, to 0.8(-1) mm diam. Exciple dark red-brown, c. 50 microns wide, but widening to c. 75 pm at the base; outermost edge usually with a narrow, hyaline zone to 8 micorns wide containing free hyphal apices; hyphae radiating in a dense pigmented matrix, c. 2-2.5 microns wide, but outer 1-2 cells broader (34 microns) and free of pigment. Hymenium 75-85 (100) um tall, hyaline, I+ blue; epithecium purplish brown. Subymenium c. 30-50 microns tall.
Chemistry: Thallus K-, C-, KC-P- UV+ yellowish white; zcorin (major) and a chemosyndrome of 4 fatty acids - two of which appear to correspond with nephrosieranic and roccellaric acids by TLC. Nothing detected by HPLC.
Substrate
Saxicolous
Attribution
Fact sheet prepared by Marley Ford (16 November 2022). Brief description, Distribution, Habitat, and Features sections copied from Coppins & Friday (2007).
References and further reading
Coppins B.J. and Friday A.M. 2007: Three new species of Bacidia s. lat. (Ramalinaceae) from Campbell Island (New Zealand). Bibliotheca Lichenologica 95: 155–164.