Neotropical Ascomycetes 3. Reinstatement of the Genus Xenolophium and Two New Species from French Guiana

Abstract

The genus Xenolophium is recognized for X. pachythele and X. applanatum, both new combinations, and their affinities to Ostropella albocincta are discussed. Two new species X. samuelsii and X. guianense are described from French Guiana. A key to the species of Xenolophium is given. Investigations of Neotropical fungi at the her? barium at New York uncovered two ascomycetes from French Guiana having large, superficial as? comata with an apical crest, slit-like ostiole and distinctive ascus morphology. Ascomatal characteristics suggested a relationship with Ostropella albocincta (Berk. & Curt.) von Hohnel and Schizostomapachythele(Berk. & Br.) Sacc, both known from tropical areas. This paper reexamines the relationships of O. albocincta, S. pachy? thele and the genus Xenolophium Sydow, with descriptions, illustrations and a key to species. Ostropella albocincta, S. pachythele, and Xenolophium are linked by similarities in ascom? atal, ascus and ascospore characteristics. Barr (1990) provides the history of Ostropella (Sacc.) von Hohnel and its relationship to these other taxa and to the genus Ostreionella Seaver. Holm and Yue (1988) present the most recent work on Schizostoma Ces. & de Not. ex Sacc. in which they tried to clarify some misconceptions that have surrounded the genus since its establishment by Saccardo in 1878 and to resolve the placement of some species. Sydow (in Stevens, 1925) established Xenolophium for two species from Hawaii, X. leve Sydow and X. verrucosum Sydow, but the genus has been in synonymy until now.