Flora of New Zealand Series

Holotype: New Zealand. South I., Nelson, Mt Arthur, 0.3 km W of Mt Arthur Hut, on calcareous rocks in low alpine area, 1340 m, 1993, L. Tibell 19654 – AK 210817.

Description : Thallus small, olivaceous, developing in rosettes, rings or tufts, 1–6 mm diam. Lobes horizontal or ±erect, 0.3–0.4 mm long, single filaments 0.01 mm, in pairs, 0.02–0.035 mm thick. Cyanobiont, Scytonema, filaments straight or slightly undulating. Hyphae 1.5–3 μm thick, in 1–3 layers longitudinally extending within the gelatinous sheath of the cyanobiont; haustoria of enlarged cells formed from short, side branches. Apothecia adnate, brown, to 0.3 mm diam., disc plane at first, with a pale, proper margin, becoming convex and immarginate. Hymenium 60–70 μm tall, I+ intensely blue. Hypothecium reddish brown, 45–50 μm. Paraphyses 1–2 μm diam., enlarged to 3 μm at apices, simple or slightly branched in upper parts. Asci cylindrical to clavate, 45–55 × 8.5–12 μm, with an amyloid cap or a faint apical ring-structure. Ascospores colourless, ellipsoidal, with a central plasma bridge when young, (6–)8.5–10.5 × 5–8.5 μm. Pycnidia brown or pale, to 90 μm diam. Conidia bacillar, 3–4 × 1 μm.

S: Nelson. Known only from the type locality.

Endemic

Illustrations : Henssen (2004: 197, fig. 1A–G).

Hertella neozelandica is characterised by: the saxicolous habit (basicolous rocks); the small, filamentous, olivaceous, tufted thallus; the lecideine, brown apothecia with a pale proper margin at first, occluded at maturity; 8-spored asci; and ellipsoidal ascospores, 6–10.5 × 5–8.5 μm. It might be mistaken for Zahlbrucknerella calcarea or Z. compacta (q.v.), but these latter taxa have lecanorine apothecia (with a thick thalline margin) and polysporous asci.