ABSTRACT: Mycoaciella (Steccherinaceae, Stereales, Basidiomycota) is a genus of resupinate, hydnaceous, corticioid fungi with a dimitic hyphal system. Presently, three taxa are accepted in the genus: M. bispora, the generic type, M. brunnea, and M. hinnulea. As a result of this microscopic study, Mycoaciella is placed in synonymy with Phlebia (Meruliaceae, Stereales), two new combinations, Phlebia bispora and P. hinnulea, are proposed, and Mycoaciella brunnea is retained in Ceraceohydnum. The new combination Phlebia badia is proposed for Odontia badia, a species with a dimitic hyphal system of simple septate generative and thick-walled skeletal hyphae. Phlebia bispora and Phlebia hinnulea possess a trimitic hyphal system consisting of thin-walled, nodose septate generative, thick-walled, aseptate skeletal, and slender, highly branched micro-binding hyphae. Resinous-capped hymenial cystidia are present in P. bispora, P. hinnulea, and P. badia. These three taxa and C. brunneum are described and illustrated.

KEYWORDS: Ceraceohydnum brunneum, Resinicium bisporum, Odontia hinnulea, Odontia badia, Acia denticulata, micro-binding hyphae

NOMENCLATURAL NOVELTIES:
Phlebia badia (Pat.) Nakasone, p. 478
Phlebia bispora (Stalpers) Nakasone, p. 481
Phlebia hinnulea (Bres.) Nakasone, p. 484