Flora of New Zealand Series

≡*Tichothecium grossum Körb, Parerga Lich.: 469 (1865).

Description : Pseudothecia developing in thalline swellings or galls on the upper surface of host, rarely at the tips of rhizomorphs on the lower surface, 0.5–4.5(–6) mm diam., often forming whitish or brownish, necrotic patches on host thallus, individual perithecia, numerous, crowded, often arranged in concentric circles, immersed at first, becoming globose at maturity, shining, carbonaceous-black, 0.05–0.1 mm diam., with a central depressed ostiole. Ascospores dark olive-brown, one cell larger and slightly more swollen than the other, slightly constricted at septum, (13.5–)15–16.5(–18.2) × 7–8.5(–9) μm, walls delicately verrucose.

S: Nelson (St Arnaud Ra.), Marlborough (Mt Tapuae-o-uenuku, Inland Kaikoura Ra., Acheron River, Molesworth), Canterbury (Kea Point, Mt Cook, Hunters Hills, Kirkliston Ra.), Otago (Mt Head, Forbes Ra., Mt Minos, Humboldt Mts, Poolburn, Manorburn, Butcher's Dam, Old Man Ra., Mt Benger, Rock & Pillar Ra., Silver Peaks, Mt Cargill, Flagstaff, Maungatua). On alpine to high-alpine rocks. First collected from Mt Tapuae-o-uenuku by Jack Scott Thomson in the 1930s and now known to be widespread in alpine regions of South Island (Galloway 2002c). Known also from Svalbard (on Umbilicaria cylindrica), Norway (on Umbilicaria arctica), Greenland (on Umbilicaria cylindrica, and U. vellea), central Spain (on Umbilicaria cinerascens) and from British Columbia (on Umbilicara polyphylla) (Hawksworth 1982; Alstrup & Hawksworth 1990; Hafellner & Sancho 1990; Santesson 1993; Alstrup & Elvebakk 1996).

Bipolar

Hosts : Umbilicaria cylindrica, U. durietzii, U. grisea, U. hyperborea, U. nylanderiana, U. polyphylla, U. subaprina, U. umbilicarioides and U. vellea – forming circular swellings to conspicuous, globose galls (reminiscent of pustules in Lasallia) on the upper surface of the host lichen, up to 6 mm diam., with a characteristic, rounded depression visible on the lower surface.

* Clypeococcum grossum is characterised by: the lichenicolous habit; pseudothecia formed in galls, the hyphal walls of which are finally united by a black clypeus (a shield-like stromatic growth over one or more ascomata); and brown, verruculose ascospores, (14–)16–20(–21) × 7–9(–10) μm.