Umbilicaria subaprina
≡Omphalodiscus subaprinus (Frey) Llano, Monogr. Lich. Fam. Umbilicariaceae: 102 (1950).
=Umbilicaria subaprina var. neozelandica Frey, Ber. Schweiz. Bot Ges. 45: 221 (1936).
Holotype: New Zealand. Marlborough, Mt Tapae-o-uenuku, 2133 m, ii.1934, J.S. Thomson T1512 [ZA 5] – G. Isotypes: CHR 160021, OTA 029675.
Umbilicaria subaprina var. neozelandica. Holotype: New Zealand. Marlborough, Mt Tapae-o-uenuku, 2000 m, 1934, J.S. Thomson – Bern. Isotypes? CHR, OTA.
Description : Thallus orbicular to irregular, monophyllous, sometimes with small, crowded secondary lobes developing towards centre of large thalli, 1.5–4(–6) cm diam., margins entire, sinuous, sometimes thickened and with a glossy, black rim, or with projecting rhizinomorphs, shallowly notched or incised. Upper surface olive-green to brownish or grey-green when wet, pale-grey to grey-brown to ±blackened when dry, sometimes noticeably whitened centrally, shallowly reticulate-ridged or faveolate, to smooth or shallowly papillate, occasionally with radiating wrinkles above umbilicus, minutely areolate (×10 lens), to granular-crystalline, with coarse whitish, crystalline granules centrally. Lower surface uniformly black, or with brownish patches at margins, to pale pinkish tan centrally and grey-brown at margins in large specimens, smooth to minutely roughened or minutely scabrid-areolate (×10 lens). Umbilicus stout, often distinctly stalked, 2–6(–8) mm diam., often with radiating lamellar structures or with deeply folded lobes. Rhizinomorphs common, often dense and entangled, in large patches or uniformly from margins to centre, mainly cylindrical, becoming flattened at or near margins, simple to squarrosely branched, 1–3(–8) mm long, rather slender, 0.1–0.3(–0.6) mm diam., whitish, pinkish, grey to blackened, with minute, lateral, black thalloconidia. Apothecia sparse and widely scattered to numerous and crowded, sessile to subimmersed, sometimes erupting from a scalloped collar of thalline tissue, round to irregular or distorted through mutual pressure (0.2–)0.5–1(–2) mm diam., disc plane, coal-black, matt, epruinose, often with a central sterile button, irregularly marginate fissure; margins raised, prominent, persistent, flexuous, to scalloped, glossy, black. Epithecium dense olive-brown, 8–15 μm thick. Hymenium colourless, 75–90 μm tall. Paraphyses slender, simple, 1–2 μm thick, apices swollen to 4–5 μm diam. Hypothecium reddish brown, opaque, 125–175 μm thick. Asci cylindrical-clavate, 60–70 × 12–15 μm. Ascospores colourless, broadly ellipsoidal to ovoid, (8.5–)10–12(–15) × 5–7.5(–9) μm. Pycnidia minute, punctiform, black, widely scattered centrally, often crowded at lobe margins. Conidia bacillar, 3–4 × 1 μm.
Chemistry : Not tested.
S: Nelson (Lake Peel, St Arnaud Ra., Wairau Valley), Marlborough (Mt Tapae-o-uenuku, Island Saddle), Westland (Pioneer Hut, Mt Alack, Mt Haidinger, Mt Haast), Canterbury (Mt Captain, Cass, Douglas Peak, Tasman Valley, Grampian Mts, Kirkliston Ra.), Otago (Watkins Dome, head of Lake Hawea, East Matukituki Valley, Mt Head, Kea Basin Rees Valley, Humboldt Mts, The Remarkables, St Bathans Ra., Mt Pisgah). On exposed alpine to high-alpine rocks and boulders in scree, subalpine herbfield and on exposed ridges and summits, 1160–3138 m. Associating with Pseudephebe pubescens, Rhizocarpon geographicum, Tremolecia atrata, Umbilicaria decussata, U. durietzii, U. krascheninnikovii, U. virginis and U. zahlbruckneri.
Endemic
Illustrations : Frey (1936a: pl. 11, fig. 3; 1949: 463, fig. 16 – as Umbilicaria durietzii); Llano (1950: 245, pl. 12, fig. 2).
Umbilicaria subaprina is characterised by: the saxicolous habit; the areolate, scabrid upper surface; the immersed to sessile apothecia (sometimes erupting through a collar of thalline tissue) with flexuous margins and a central sterile button or papilla, but lacking gyrose ridges; cylindrical to flattened rhizinomorphs in patches on the lower surface and projecting from lobe margins; and a smooth to minutely scabrid-areolate, black to pale-tan lower surface, with thalloconidia.
