Flora of New Zealand Series

Holotype: New Zealand. Campbell I., rock outcrops at summit of Mt Azimuth, 485 m, 3.i.1970, H.A. Imshaug 46564 – MSC. Isotype – CHR.

Description : Thallus crustose irregularly spreading, to 0.1 mm thick, creamy-grey, areolate. Apothecia dark brown-black, red-brown when moist, lecideine, orbicular, (0.4–)0.7–0.9(–1.2) mm diam., immersed, with a white, raised pseudothalline margin 0.08–0.12 mm wide, separated from thallus by a thin crack; disc shallowly concave, epruinose, without a visible proper margin. Epithecium pale orange-brown, 50–60 μm thick. Hymenium colourless, 150–180 μm tall, I+ blue. Paraphyses slender, 1.5–2 μm diam., richly branched and anastomosing, scarcely swollen at apices and without a pigmented cap. Hypothecium orange-brown, 150–180 μm thick. Asci cylindrical-clavate, 85–100 × 30–35 μm, Trapelia -type. Ascospores colourless, broadly ellipsoidal, (25–)27–30 × (12–)15–18(–19) μm. Pycnidia not seen.

Chemistry : Thallus K−, C+ red, Pd−; containing gyrophoric acid.

S: Otago (Mihiwaka), Southland (Borland Saddle). C: (Mt Azimuth, Mt Lyall, Mt Fizeau). On rock outcrops in fellfield and cliffs, the Campbell I. populations associating with the lichens Lecidea lygomma and species of Psoroma and Placopsis (Fryday 2004a). The Otago material seen formed mosaics with Lecanora farinacea and Lecidella sublapicida.

Endemic

Trapelia macrospora is characterised by: the saxicolous habit; the creamish or cream-grey, areolate thallus; the innate apothecia with a dark brown-black, epruinose disc; hymenium and hypothecium 150–180 μm tall and thick; and large ascospores, 25–30 × 12–19 μm.