Flora of New Zealand Series

Holotype: New Zealand. Campbell I., outcrops on summit of Beeman Hill, 195 m, 14.i.1979, H.A. Imshaug 47051 – MSC. Isotypes – CHR, HO, BG.

Description : Thallus effuse, areolate, 0.25–0.4 mm thick, pale whitish to lead-grey, without a marginal prothallus. Areolae flat, 0.7–1 mm diam. Apothecia black, epruinose, lecideine, rounded, sessile, plane at first soon becoming convex, 0.7–1.2 mm diam., proper margin persistent, concolorous with disc. Epithecium dark-aeruginose, 30–35 μm thick (K+ blue, N+ red). Hymenium colourless, 100–120 μm tall; subhymenium colourless 40–45 μm thick. Paraphyses simple, easily separating, 2–2.5 μm thick, apices swollen to 5 μm diam., with a dark-blue pigmented cap. Hypothecium 35 μm thick, dark-blue (K+ blue, N+ red). Asci cylindrical, Lecanora -type, 80–85 × 15–17 μm. Ascospores hyaline, 1-septate, 12–16(–18) × 6–8 μm. Exciple of radiating hyphae with enlarged cells (8.5–15 μm diam.) with dark-blue pigment on outer walls of hyphae, continuous under hypothecium. Pycnidia not seen.

Chemistry : TLC−, all reactions negative.

A: (Hooker Hills, Mt Eden, Adams I.). C: (Mt Lyall, Menhir Peak, Mt Azimuth, Mt Dumas, Camp Cove, Mt Sorenson, Mt Eden). A common species on rocky crags and outcrops in scrub and grassland, associating with the lichens Fuscidea subasbolodes, Pannaria dichroa, Pertusaria sp., Placopsis sp. and Rimularia psephota.

Endemic

Megalaria imshaugii is characterised by: the saxicolous habit; the effuse, whitish to lead-grey, areolate thallus; black, epruinose, apothecia, 0.7–1.2 mm diam.; and ascospores 12–16(–18) × 6–8 μm.