Flora of New Zealand Series

Type : * Clypeococcum cladonema (Wedd.) D.Hawksw. [= * Lecidea cladonema Wedd.]

Description : Lichenicolous, parasitising and often eventually causing necrotic patches on host lichen, gall-forming. Ascomata pseudothecia, in prominent globose galls, globose, ostiolate, not distinctly beaked, without periphyses, black, numerous, in groups united by a common black clypeus, walls consisting of compacted interwoven hyphae (textura intricata). Hamathecium of distinct, filiform, colourless, septate, branched and anastomosing paraphysoids or pseudoparaphyses. Asci subcylindrical, shortly stalked, bitunicate, with a distinct internal apical beak, 8-spored. Ascospores ellipsoidal, brown to dark-brown, 1-septate, the septum developed below the centre of the spore, walls distinctly minutely verrucose.

Clypeococcum (Hawksworth 1977a) is a genus of seven species worldwide (Ertz 2004a), included in the family Dacampiaceae (Hawksworth 2003; Pennycook & Galloway 2003; Eriksson et al. 2004). It occurs as a parasite on Hypocenomyce scalaris (Hawksworth 1980b; Triebel 1989), Cetrelia and Parmelia (Hawksworth 1977a), Placopsis contortuplicata (Øvstedal & Hawksworth 1986), species of Umbilicaria (Hawksworth 1982: 379; Øvstedal & Hawksworth 1986: 58; Hawksworth & Diederich 1988: 306; Alstrup & Hawksworth 1990: 22; Santesson 1993: 70) and on Cetraria islandica (Hafellner 1994b). The genus differs from Polycoccum (q.v.), where no clypeus structure is developed, and the walls of the ascomata consist of angular, compressed, pseudoparenchymatous cells (textura angularis) and not interwoven hyphae (Hawksworth 1980b: 168). All species of Clypeococcum have pseudothecia merged by dark-brown, stromatic hyphae, and some with explicitly parasitic life habit, which is otherwise rare in lichenicolous ascomycetes (Rambold & Triebel 1999: 140).

One species is known from New Zealand and was first reported from specimens of Umbilicaria vellea collected on the Rock & Pillar Range (Hawksworth & Diederich 1988: 306). It is now known more widely on several species of Umbilicaria (q.v.) in New Zealand (Galloway 2002c). Material of Clypeococcum -infected Umbilicaria from New Zealand was earlier incorrectly designated as Lasallia sp. (Galloway 1985a: 203; 1992: 19), the conspicuous superficial galls being misinterpreted for the pustules that are a common feature of species of Lasallia, a genus not occurring in New Zealand. Species of Clypeococcum should also be looked for as parasites of Placopsis.