Flora of New Zealand Series

Type : Arthrorhaphis flavovirescens (A.Massal.) Th.Fr. (see Jørgensen & Santesson 1993: 881) [=A. citrinella (Ach.) Poelt].

Description : Thallus crustose to squamulose-lobate and sometimes hollow, without a marginal prothallus, with or without the vivid yellow-green pigment rhizocarpic acid, initially often parasitic on species of Baeomyces or Dibaeis, rarely persistently parasitic on Cladonia or Melanelia or Pseudocyphellaria. Medulla with or without calcium oxalate crystals. Ascomata apothecia, black, in early stage with a distinct concolorous margin. Epithecium green-brown or blackish green, the colour intensifying with nitric acid. Hamathecium of paraphyses, thin, weakly branched at apices, tips not swollen. Hymenium hyaline to pale-brown, sometimes with oil droplets. Asci clavate, 8-spored, slightly thickened at apex, K/I−, with an ocular chamber. Ascospores colourless, cylindrical to acicular, with a perispore, 3–16(rarely more)-septate. Conidiomata unknown. For additional details see Obermayer (1994, 1996, 2001; Ihlen 1998: 35–42).

Arthrorhaphis is a widespread, temperate, alpine (mainly bipolar) genus of c. 11 species included in the monogeneric family Arthrorhaphidaceae (Poelt & Hafellner 1976; Obermayer 2001; Kirk et al. 2001; Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005). Jørgensen & Santesson (1993) proposed the conservation of the generic name Arthrorhaphis over Raphiospora A.Massal. lectotypified by R. flavovirescens. Four taxa are recorded from New Zealand (Galloway & Bartlett 1986; Kondratyuk & Galloway 1994), three occurring in high-alpine habitats as free-living taxa containing the yellow-green pigment rhizocarpic acid (A. alpina and two varieties of A. citrinella), the fourth (A. grisea), being parasitic on species of Pseudocyphellaria in lowland habitats. Lichenicolous fungi growing on Arthrorhaphis are discussed by Hafellner & Obermayer (1995) and Hansen & Obermayer (1999).