Flora of New Zealand Series

Holotype: New Zealand. Chatham I. "Big Bush", on loose bryozoan limestone outcrops, 40 m, ii.1985, B.P.J. Molloy s.n. CHR! – isotypes BM, GZU.

Description : Thallus greenish white, not blackened around the ascocarps, dull, immersed in substratum, continuous, without crystals, without marginal prothallus. Photobiont green, ? Trentepohlia. Perithecia simple or with fused ostioles and fused walls (astrothelioid) without pseudostromatic tissues, without crystals, conical, not distinctly flattened, erumpent from the substratum, exposed, 0.5–0.7 mm diam., 0.3–0.5 mm tall. Ascocarp wall completely carbonised, without distinct clypeus, up to 150 μm thick. Ostiole brown, obconical, skewed, 100–200 μm diam. Hamathecium not inspersed with oil droplets, not gelatinised, I−. Interthecial hyphae true paraphyses, only branched at tips, 1 μm thick. Periphyses absent. Asci with saggitiform ocular chamber (Aptroot 1991: 153, fig. 68), 80–110 × 12–15 μm. Ascospores uniseriate, red-brown, fusiform 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 diam., wall completely carbonised, up to 40 μm thick. Conidia acrogenous, colourless, filiform, 6–10 × 0.2–0.4 μm.

Chemistry : TLC−, all reactions negative.

S: Westland (Bullock Creek). Ch: On lowland limestone, still very poorly collected.

Endemic

Illustrations : Aptroot & Mayrhofer (1991: 220, figs 1–6; 221, fig. 7); Aptroot (1991a: 144, fig. 7; 153, fig. 68; 155, fig. 90).

Lithothelium australe is characterised by: the saxicolous habit (limestone); the greenish white, thallus, superficial or immersed in substratum; simple to fused (astrothelioid) perithecia; 3-septate, fusiform, red-brown ascospores, 20–26 × 6–8 μm; and black pycnidia with colourless, filiform conidia, 6–10 × 0.2–0.4 μm.