Flora of New Zealand Series

Type : Leptorhaphis oxyspora (Nyl.) Körb. [=Verrucaria oxyspora Nyl.]

Description : Thallus lacking or appearing whitish grey to greenish, smooth not well-delimited, immersed in substratum, of colourless, thin-walled hyphae, in a few species loosely associated with Trentepohlia. Ascomata perithecia, reddish brown, dark-brown to black, smooth and glossy, scattered, solitary or sometimes confluent, rounded to ellipsoidal, immersed, to superficial, dimidiate, hemispherical, ostiolate. Involucrellum of dark-brown to greenish black, smooth, thin-walled hyphae, intermixed with bark cells forming a clypeate tissue. Exciple developed within involucrellum, extending below centrum in some species, of radially compressed, pseudoparenchymatous cells, colourless to brown. Hamathecium of pseudoparaphyses, of cellular, septate, branched, anastomosing hyphae forming a compact net. Periphyses and periphysoids absent. Hymenial gelatine orange or blue-green, never deep-blue in I. Asci cylindrical–clavate, bitunicate, 8-spored, or exceptionally 16-spored. Ascospores in 1 or 2 bundles in asci, each bundle parallel sometimes twisted helically, fusiform–acicular, arcuate or sigmoid, pointed at one or both ends, colourless to pale-brown, 1- to 5-septate, not constricted at septa, thin and smooth-walled, without a perispore. Conidiomata pycnidia, black, shiny, rounded to ellipsoidal, scattered between ascomata, immersed to subsuperficial, conical to subglobose, ostiolate. Wall of dark-brown, thin-walled hyphae, intermixed with bark cells forming a clypeate tissue. Condiogenous cells ampulliform to lageniform, colourless, thin-walled and smooth. Macroconidia colourless, acicular–fusiform, arcuate, thin-walled, smooth, similar in size to ascospores, simple. Microconidia colourless, bacillar, thin-walled, smooth.

Leptorhaphis a genus of 14 species (Aguirre-Hudson 1991; Kalb et al. 1995; Aguirre-Hudson et al. 2002) is included in the family Naetrocymbaceae (Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005). The genus is monographed by Aguirre-Hudson (1991) who discusses its relationships with the genera Arthopyrenia, Celothelium, Cresporhaphis, Sarcopyrenia and Rhaphidicyrtis, previously referred to Leptorhaphis. Hungarian species are discussed by Aguirre-Hudson et al. (2002). Species of Leptorhaphis are saprobic on tree bark or rarely lichenicolous, and are characteristic components of pioneer fungal-lichen communities, with some appearing to be almost exclusively host-specific. Species are widespread in boreal and temperate regions of Europe and North America, but generally they are overlooked because of their small size. One lichenicolous species is recorded from New Zealand (Kalb et al. 1995). The New Zealand taxa Verrucaria beloniza Stirt. and V. macrocyrtospora C.Knight, formerly referred to Leptorhaphis, are now placed in Rhytidiella (q.v.).