Flora of New Zealand Series

Type : Agonimia tristicula (Nyl.) Zahlbr. [=Verrucaria tristicula Nyl.]

Description : Flora (1985: 4). See also Breuss (2002a: 90).

Agonimia is a genus of c. 9 known species included in the family Verrucariaceae (Kirk et al. 2001; McCarthy 2001c; Eriksson et al. 2004; Pennycook & Galloway 2004). The two European taxa in the genus were shown to be united by the following characters: a minutely squamulose thallus with an irregular, conical-papillate upper cortex; a thick, 3-layered perithecial wall; and ellipsoidal, densely muriform ascospores. Agonimiella, a monospecific genus in the Verrucariaceae, was recently described by Harada (1993c) to accommodate material from Japan resembling Agonimia tristicula (the generitype of Agonimia Zahlbr.) but differing from it in a number of characters viz.: (1) Agonimia tristicula has a papillate upper cortex, a diagnostic character of Agonimia (Coppins & James 1978), these are absent in Agonimiella; (2) ascospores become brown in Agonimia but remain hyaline in Agonimiella; (3) perithecial walls of Agonimia tristicula are multilayered with an outer black and an inner hyaline layer, while those of Agonimiella are uniform, black and composed of thin-walled hyphae; (4) the subhymenium is biconvex in Agonimia tristicula but concave in Agonimiella; (6) periphyses are short and simple in Agonimia tristicula but long, sparsely branched and anastomosing in Agonimiella; (6) texture of the perithecia is very rough and not fibrous in Agonimia tristicula but is smooth and frequently fibrous in Agonimiella. However, Aptroot et al. (1997: 12–13) showed Agonimiella to be conspecific with Agonimia by demonstrating the presence of cortical papillae and observing brown mature ascospores in material of A. pacifica collected in Papua New Guinea. Useful notes on the genus and three additional European species of it are given by Sérusiaux et al. (1999: 6–14), and a new species from Poland was described by Czarnota & Coppins (2000). McCarthy (2001c: 159–160) discusses the genus in Australia. One species is known from New Zealand.