Arthonia haematommatum
Holotype: New Zealand. Otago, Old Man Range, Mulvena's Road, 1155 m, on dead Hymenanthera [Melicytus alpinus], in apothecia of Haematomma alpinum, 9.viii.1970, P. Child 652 – CHR.
Description : Lichenicolous, blackening host apothecia. Apothecia developing in host hymenium and blackening the disc, to 1.5 mm diam., and 0.2 mm thick, black, rounded, flat to slightly convex. Hymenium to 60 μm tall, colourless, I+ blue; epithecium brown. Hypothecium brown. Paraphysoids 1.5–2 μm diam, apices with dark-pigmented apical caps, 2–4 μm diam. Asci fissitunicate, clavate, 45–55 × 17–22 μm, 4–6(–8)-spored. Ascospores narrowly ovoid to soleiform, colourless at first becoming brown (2–)3-septate, the end cell enlarged, 13–16 × 5–7 μm, with a thick perispore.
S: Canterbury (Cave Stream), Otago (Mulvena's Road, Old Man Ra.). On apothecia of subalpine-alpine species of Haematomma.
Endemic
Hosts : Haematomma alpinum, H. babingtonii.
Illustrations : Kalb et al. (1995: pls 1–3).
* Arthonia haematommatum is characterised by: the lichenicolous habit (parasitising ascomata of Haematomma alpinum and H. babingtonii); 4–6(–8) spored asci developing in the hymenium of the host; and 3-septate ascospores, becoming brown at maturity, 13–16 × 5–7 μm. It is distinguished from A. clemens by the nature of the host lichen, and the differing dimensions of the asci and ascospores.
