Six new species of Gloeocystidiellum (G. fimbriatum, G. marianus, G. sinuosum, G. tropicalis, G. turpe, and G. wakullum) from the southeastern United States are described and illustrated. Culture descriptions are provided for three species. Studies of lignicolous fungi of the southeastern United States have revealed six new species of Gloeocystidiellum (Corticiaceae). The basidi- ocarps are described and illustrated. Cultural descriptions are provided for three species. The materials and methods used are those included in Burdsall and Nakasone (1981) with color citations from Kornerup and Wanscher (1967) indicating page number, column, and line, respectively. DESCRIPTION OF SPECIES Basidiocarp broadly effused, membranous, up to 0.3 mm thick, soft, adherent; fertile area continuous, appressed pubescent, white when fresh, pale yellow (3A3) to yellowish white (4A2) when dried; margin up to 3 mm wide, very thin, irregular, concolorous with hymenium, powdery to fimbriate or with small cordons; subiculum woolly, concolorous with fertile area, up to 0.2 mm thick. Hyphal system monomitic; subiculum a textura intricata, hyphae distinct, 3-5 ,tm diam. with walls up to 0.5 ,tm thick, hyaline, smooth, frequently branched, long-celled, simple septate; cordons up to 150 tLm diam., merely an aggregation of hyphae, a textura porrecta, outer surface coated with layer of hyaline crystals, hyphae of