Cameronia tecta
Cameronia tecta is a species of crustose lichen in the family Cameroniaceae. It forms a thin to moderately thick, pale beige-brown to greyish-brown crust on rock, typically found in sheltered crevices and overhangs. Unlike the related Cameronia pertusarioides, which grows on exposed dolerite, this species occurs on quartzite and other metamorphic rocks. It is known only from alpine sites in southwestern Tasmania.
Taxonomy
Cameronia tecta was described in 2012 by Gintaras Kantvilas as one of two species placed in that newly erected genus. In the protologue, Cameronia was treated as most likely belonging to the subclass Ostropomycetidae, but its position was considered uncertain on morphology alone. DNA sequence data supported the monophyly of Cameronia and its placement within Ostropomycetidae, while leaving its closest relatives unresolved. Because Cameronia lacks clear close relatives in the available phylogeny and differs morphologically from other lineages in Ostropomycetidae, H. Thorsten Lumbsch and co-authors proposed the family Cameroniaceae for the genus. The epithet tecta means "concealed" and refers to the species' tendency to grow hidden in rock clefts and under overhangs.Description
The lichen forms a thin to moderately thick crust that is pale beige-brown to mottled greyish-brown or yellowish-brown. Thalli are irregular in outline, can reach about 10 cm across, and are usually deeply cracked, while the surface is otherwise mostly smooth. The thallus is typically 0.2–0.5 mm thick and is often poorly delimited, though it may have a blackish, -like leading edge. It has a discontinuous about 5–20 micrometres thick, and a white to orange-brown, chalky medulla that contains minute crystals visible under polarised light. The is a coccoid green alga. The thallus is UV−.The fruiting bodies are immersed, perithecioid perithecia that occur in the thickest parts of the thallus and are often clustered together. Externally, they are usually indicated only by tiny greyish-black surface depressions around the ostiole, about 0.05–0.1 mm wide. The perithecia are more or less spherical and about 160–280 μm wide, with a brownish about 10–20 μm thick and no involucrellum. are about 1–2 μm thick, and the hymenial gel contains scattered oil droplets and some algal cells. The asci occur in small clusters, are four-spored, and measure about 90–140 × 35–60 μm. The ascospores are hyaline and, broadly ellipsoid to ovate, measuring about 34–78 × 22–36 μm.
Asexual reproduction occurs via immersed pycnidia about 200–250 μm wide, which may form small swellings with minute, dark speck-like ostioles. The conidia are mostly bacilliform and measure about 6–8 × 1 μm. Chemically, the species contains an unknown compound interpreted as a triphenyl, and its UV spectrum and chromatographic behaviour were reported as resembling deacetylbutlerin A.