Flora of New Zealand Series

Type : Delisea pseudosticta Fée [= * Plectocarpon pseudosticta (Fée) Fée]. For additional synonymy see Hawksworth & Galloway (1984: 86), Diederich & Etayo (1994) and Ertz et al. (2005: 8).

Description : Lichenicolous on macrolichens. Ascomata apothecia, often forming galls on the host thallus (on either or both upper and lower surfaces) without damaging the host in other ways, rounded or rarely elongate, discrete, brown or black, often with a verrucose or papillate surface, often divided into several confluent or isolated apothecia-like or perithecia-like locules by stromatic tissues. Exciple colourless to brown, composed of elongate cells, continuous under the hypothecium, reduced in most species having a strong development of stromatic tissue. Stromatic tissue often ±covering the hymenium and dividing it into several locules, sometimes also developed under the fertile hymenium, often dark-brown to black, with a greenish pigment dissolving in K. Hypothecium colourless to brown, well-developed or reduced. Hymenium hyaline or pale-brown, often green in K. Hamathecium of paraphysoids, septate, anastomosing, 2–3 μm diam., apices not swollen. Asci Roccella -type, 2–8-spored, clavate–cylindrical, thick-walled, fissitunicate. Ascospores 3-, more rarely 1–6-septate, fusiform, sometimes constricted at middle septum, with a distinct perispore, colourless, rarely brownish when over-mature, epispore smooth, perispore rarely ornamented when over-mature. Conidiomata pycnidia, immersed in stromata or galls, subspherical, wall hyaline or brown. Conidia simple, bacillar, colourless.

Plectocarpon is a genus of gall-forming fungi included in the family Roccellaceae (Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005; Ertz et al. 2005). It is distinguished by rounded mono- or multi-locular, often stromatic ascomata with a reduced, non-carbonised exciple, asci Roccella -type, (1–)3(–6)-septate, colourless ascospores with a distinct perispore and anastomosed paraphysoids. Some 16 species are described, all lichenicolous on macrolichens, belonging mainly to the Peltigerales. Nomenclature is discussed by Hawksworth & Galloway (1984), and a monograph of mainly Northern Hemisphere taxa is available (Diederich & Etayo 1994). Two species were subsequently described from Papua New Guinea from Lobaria and Pseudocyphellaria hosts (Aptroot et al. 1997: 137–140), a tropical species from Coenogonium (Cáceres et al. 2001), a species from California parasitising Niebla robusta (Hafellner et al. 2002: 312–313), a new species on Peltigera leucophlebia from British Columbia (Ertz et al. 2003), and a new species from Roccella portentosa in Chile (Follmann & Werner 2003). Very recently, a world monograph of all 32 known species was published (Ertz et al. 2005). Seven species are recorded from New Zealand, occurring as a parasite on both upper and lower surfaces of species of Pseudocyphellaria and Sticta (Hawksworth & Galloway 1984; Galloway 1988a; Diederich & Etayo 1994; Kondratyuk & Galloway 1995b; Ertz et al. 2005).