Cliostomum Fr.
Type : Cliostomum corrugatum (Ach.) Fr. [=Lecidea corrugata Ach.]
Description : Flora (1985: 125–126). See also Ekman (1997: 18–19).
Cliostomum, included in the family Ramalinaceae (Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005) is characterised by: a crustose thallus; lecideine apothecia; 8-spored asci (Biatora -type), with an ocular chamber and an amyloid tholus, which has a convergent masse axiale with an amyloid zone above; the region of the tholus immediately adjacent to the masse axiale tending to be more intensely amyloid. Ascospores are hyaline, thin-walled, ellipsoidal and usually 1-septate or rarely simple or up to 3-septate. Species usually have numerous, conspicuous pycnidia with dark brownish, K+ purplish walls. Thallus chemistry includes atranorin usually accompanied by fatty acids. Seven species are known worldwide (Ekman 1996a) of which one occurs in New Zealand (Kantvilas & Elix 1995; Ekman 1997). Cliostomum is separated from Bacidia and Bacidina on account of the wide and irregularly shaped cell lumina in the proper exciple; the often crystal-inspersed epithecium and proper exciple; the 1–3-septate, bacillar spores; and the branched conidiophores with subglobose to ellipsoidal to short-bacillar conidia. Cliostomum is closely related to Biatora, but the latter genus differs in having sparsely branched, ampuliform (not cylindrical) conidiogenous cells and in having cylindrical, almost parallel and distinctly radiating excipular hyphae (Ekman 1996a: 40).
