Flora of New Zealand Series

C: Known only from the type locality.

Holotype: New Zealand. Campbell I., rock outcrops and upland peat bog at W end of Lyall ridge, 215 m, 29.xii.1969, R.C. Harris 4733 – MSC.

Description : Thallus immersed, visible only adjacent to apothecia, very thin, 0.05 mm thick, pale-brown, flake-like. Apothecia black, lecideine, rounded, sessile, constricted at base, 0.4–0.7 mm diam., disc plane with a persistent, raised, proper margin, 0.05–0.1 mm thick. Epithecium 30–35 μm thick (K+ blue, N+ red). Hymenium colourless, but with vertical red-brown (K+ purple) streaks in thick sections, 100–120 μm tall; subhymenium colourless, 15–20 μm thick. Paraphyses simple, readily separating, 1.5–2 μm thick, apices swollen to 4 μm diam., with a dark-blue pigmented cap. Hypothecium to 35 μm thick, dark-blue. Asci clavate, 85–90 × 30–35 μm, Lecanora -type. Ascospores hyaline, (25–)28–36 × (11.5–) 14–17 μm. Exciple of radiating hyphae with enlarged cells (8.5–15 μm diam.), with red-brown (K+ purple) pigment in outer walls of hyphae, continuous beneath hypothecium. Pycnidia not seen.

Chemistry : TLC−, all reactions negative.

Endemic

Megalaria macrospora is characterised by: the saxicolous habit; the large ascospores, (25–)28–36 × (11.5–)14–17 μm, and the presence of a red pigment (K+ purple) in the exciple.