Lithothelium australe
Family
Pyrenulaceae
Flora category
Lichen – Native
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Structural class
Lichens - Crustose
Current conservation status
2018 | Data Deficient
Brief description
Grey, grey-green crust (with immersed thallus) inhabiting limestone. Fruiting bodies conical, black.
Distribution
Endemic. New Zealand. South Island (North Westland - Bullock Creek). Chatham Islands/Rekohu (Chatham Island - known so far from two sites: Big Bush and Te Matarae Road, see de Lange 2022).
Habitat
Hard, crystalline limestone, where it has been found on exposed karrenfield.
Detailed description
Thallus when moist grey, grey-green, drying white, dull, immersed in substrate such that it resembles weathered limestone, continous without marginal prothallus. Photobiont green. Perithecia numerous, simple or with fused ostioles and fused walls, lacking pseudostromatic tissues and crystals, conical, erumpent (not flattened) from substratum, exposed, 0.5-0.7(-0.9) mm diameter, 0.3-0.6 mm tall. Ascocarp wall carbonised, without distinct clypeus, up to 150 μm. Ostiole brown, obconical, skewed 100-200 μm diameter. Hamathecium not inspersed with oil droplets, not gelatinised, Iodine negative. Interthecial hyphae true paraphyses, only branched at tips. 1 μm thick. Periphyses absent. Asci with saggitiform ocular chambers, 80-100 × 12-15 μm. Ascospores uniseriate. red-brown, fusciform with subacute apices, symmetrically septate, not constricted at septa 20-26 × 6-8 μm; with 3 distosepta, 1 μm thick. Endospore up to 3 μm thick. Spore wall smooth, without granules, without gelatinous sheath. Pycnidia black, 100-200 μm diameter, wall completely carbonised, up to 40 μm thick. Conidia acrogenous, colourless, filiform, 6-10 ×0.2-0.4 μm.
Chemistry: TLC-, all reactions negative.
Similar taxa
Lithothelium is perhaps most similar to Pyrenula. The New Zealand Pyrenula differ from Lithothelium australe by their corticolous / lignicolous rather than saxicolous habit, mostly united rather than usually simple perithecia united by a common stroma, unbranched paraphyses, and mostly broadly ellipsoidal rather than fusiform ascospores that range from 30-70 × 11-35 μm rather than 20-26 × 6-8 μm. In the field Lithothelium australe is best recognised by the inconspicuous, immersed thallus, that is grey to grey-green when wet, whitish when dry, and numerous, erumpent, black, simple or fused perithecia. The ascospores are red-brown and usually 3-septate. Pycnidia are black, minute and abundant.
Substrate
Saxicolous (limestone)
Etymology
australe: Southern, from the Latin australis
Attribution
Fact Sheet prepared for NZPCN by P.J. de Lange (3 June 2022). Description modified from Aptroot & Mayrhofer (1991) by P.J. de Lange.
References and further reading
Aptroot, A.; Mayrhofer, H. 1991: Lithothelium australe spec. nova, a new lichen from New Zealand. Mycotaxon 41: 219-222.
de Lange P. 2022: iNaturalist observation. https://inaturalist.nz/observations/119556818. Date accessed: 2 August 2022.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Lithothelium australe Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/lithothelium-australe/ (Date website was queried)