Genus Biscogniauxia
Key to Taxa of Biscogniauxia
Accepted Taxa
List of Names

Yu-Ming Ju
Michael J. Adams

Stromata applanate, effused-pulvinate, or raised-discoid, solitary or confluent, with or without raised margins, bipartite with outer layer dehiscent, often adhering to overlying bark; innermost layer at first bearing anamorph or fugaceous papyraceous remains of anamorph, at length attaining a characteristic mature white, dark brown, or black surface color; mature stromata lacking KOH-extractable pigments, plane or with inconspicuous perithecial mounds; carbonaceous tissue immediately beneath surface; tissue between perithecia woody or carbonaceous; tissue beneath perithecia inconspicuous or conspicuous, composed of fungal tissue, host tissue, or both.

Perithecia obovoid, tubular, or long tubular, monostichous, with or without carbonaceous stromatal material surrounding individual perithecia.

Ostioles at the same level as stromatal surface or lower than stromatal surface and with openings punctate, or higher than stromatal surface and with openings papillate; one ostiole sometimes serving several perithecia.

Asci eight-spored, cylindrical, short-stipitate, persistent, with apical ring discoid, amyloid or infrequently inamyloid; ring in some taxa staining light blue in apical part and darker blue below.

Ascospores pale brown, light brown, brown, dark brown, or blackish brown, unicellular in both immature and mature ascospores or with mature ascospores bearing a hyaline cellular appendage, or, in one species, with both cells often remaining hyaline, ellipsoid or short fusoid, inequilateral, slightly inequilateral, or nearly equilateral, with acute, narrowly rounded, or broadly rounded ends, with straight or sigmoid germ slit spore-length to much less than spore-length, or lacking germ slit; perispore indehiscent in 10% KOH; epispore smooth or occasionally ornamented.

Cooke (1883c) divided Nummularia taxa into two sections: section A for taxa with a concave stromatal surface and section B for taxa with a convex stromatal surface. Pouzar (1986) recognized two sections for Biscogniauxia: Biscogniauxia and Scleraster Pouzar. These two sections were separated on morphology of stromatal margins and on colors and amounts of the stromatal tissue beneath the perithecial layer. Whalley and Laessøe (Whalley et al., 1990a, 1990b) erected section Appendiculata to accommodate taxa with appendaged ascospores. We do not assign Biscogniauxia species to sections or subgenera because the boundaries between the established sections are not well-delimited and may become less so when more collections have been studied. For instance, Biscogniauxia cinereolinacina and B. repanda were placed by Pouzar (1986) in sections Biscogniauxia and Scleraster, respectively. It is our feeling that these two species are closely related and should not be separated into two different sections. Each has a reduced amount of carbonaceous tissue encasing each individual ostiole and a bilateral ascospore germ slit. Likewise, Biscogniauxia fuscella and an unnamed Guadeloupe collection GUAD-213 that was discussed above represent smudges on the boundaries between those taxa with appendaged ascospores and those without appendaged ascospores.