Flora of New Zealand Series

Holotype: New Zealand. South I., Otago, Head of Rockburn, south end of Park Pass, on tops of boulders on ridge, associating with Menegazzia inflata, 1433 m, 16.v.1968, D.J. Galloway 68352 – CHR 378718.

Description : Thallus monophyllous, orbicular to irregular, 1–2.5(–6) cm diam., margins entire, slightly wavy, to delicately notched or incised, conspicuously black-rimmed in places, and here and there with clusters of small, bushy, projecting, black rhizinomorphs. Upper surface pale olive-green to grey-green when wet, pale grey to grey-brown or charcoal-grey when dry, coriaceous, here and there with a sparse, white pruina, smooth, occasionally roughened or scabrid-areolate in patches, or with shallow wrinkled ridges centrally. Lower surface coal-black from margins to centre, minutely roughened to markedly scabrid-areolate (×10 lens). Umbilicus compact, 2–6(–8) mm diam. Rhizinomorphs clustered at margins, exposing varying areas of lower surface, or in a dense, entangled mat from margins to centre, pale-grey to black, mainly cylindrical, slender and delicate, 1–3 mm long, 0.1 mm diam., simple to mainly squarrosely branched, apical parts with minute coralloid thalloconidia. Apothecia prominent, subimmersed and flush with surface of thallus, (0.5–)1–2(–3.5) mm diam., round to subirregular, solitary or in small groups or lines; disc black, matt, flat, rarely subconvex, epruinose; margins persistent, thin, black, slightly glossy, projecting slightly above surface of disc, entire to scalloped or crenulate, occasionally with small, black, projecting rhizinomorphs. Epithecium red-brown, 12–20 μm thick. Hymenium pale yellow-brown to pale reddish brown, 69–75(–90) μm tall. Paraphyses slender, 1–2 μm thick, apices swollen, red-brown, 5–7 μm diam. Hypothecium 200–300 μm thick, upper 125–150 μm yellow-brown, opaque, lower parts, dense brown-black. Asci rather infrequent, clavate with a tapering narrow foot, 70–90 × 20–27 μm. Ascospores colourless, broadly ellipsoidal to ovoid to subglobose, 13–15(–16.5) × 7–10(–12) μm. Pycnidia occasional to frequent at or near margins, black, punctiform, 0.1–0.2 mm diam. Conidia bacillar, 3.5–5 × 1 μm.

Chemistry : Medulla K+ yellow→red, C+ red, Pd−; containing norstictic and gyrophoric acids.

S: Otago (Matukituki Valley, Park Pass, Harris Saddle, North Col), Southland (Gertrude Valley). On exposed rocks and boulders in subalpine to alpine habitats close to the Main Divide of the Southern Alps between latitudes 44º 25's and 44º 47's, at an altitude of 1000–1515 m.

Endemic

Illustrations : Galloway & Sancho (2005: 18, figs 1, 2).

Umbilicaria murihikuana is characterised by: the saxicolous habit; the monophyllous thallus (1–2.5, rarely to 6, cm diam.); the smooth upper surface; black rhizinomorphs clustered at margins and in patches or covering lower surface; prominent, flat, black subimmersed apothecia (0.5–3.5 mm diam.), sometimes with projecting rhizinomorphs; broadly ellipsoidal to ovoid or subglobose ascospores, 13–15(–16.5) × 7–10(–12) μm; and norstictic acid (K+ yellow→red) in the medulla.