Mycena moconensis, a new species of section Polyadelphia from Yaboty Biosphere Reserve (Misiones, Argentina)

NIVEIRO, NICOLÁS; POPOFF, ORLANDO FABIÁN; DESJARDIN, DENNIS; ALBERTÓ, EDGARDO

San Jose

Congreso; VII Congreso Latinoamericano de Micología; 2011

Mycena (Pers.) Roussel comprises approximately 500 species, widely distributed in the world. It is a polyphyletic genus where a comprehensive study of molecular data is needed to clarify the infrageneric classification and to aid in species circumscriptions. There are 114 species of Mycena so far recorded in Argentina. Most of them have been found in the Andino-Patagonic forest and northwestern Argentina, whereas in the Paranaense forest, only 6 species are known. During a survey of the species of Agaricomycetes of Northern Argentina, we recently collected some specimens that do not match any other known species of Mycena and we are here in proposing as the new species M. moconensis in section Polyadelphia. Macroscopic description is based in fresh material and microscopic features are described from material mounted in KOH 5%, phloxine (1%), and Melzer?s reagent. Herbarium specimens are deposited in CTES, BAFC and LIL. This beautiful new species is characterized by small bicoloured basidomata with yellow to orange yellow or golden pileus and magenta to purple stipe. The following combination of features indicate that this species belongs to Section Polyadelphia, small basidiomata with few lamellae, thin stipe with radiating basal mycelium, cheilocystidia densely covered with simple excrescences, pip- shaped basidiospores, and a non-gelatinous pileipellis composed of hyphae densely ornamented with small spinulae. Mycena moconensis could be confused with M. coprinoides P. Karst. sensu Raithelh., a species previously recorded in Argentina, but differs, however, in forming a pale yellow to pale ochraceous pileus with a weakly striate margin, crowded and adnexed-adnate lamellae, a pale yellow stipe with a darker base, and fusiform cheilocystidia. The presence of a citron yellow to barium yellow pileus, sulcate-striate margin, adnate-decurrent, distant lamellae and pyriform to clavate cheilocystidia with excrescences also resembles Mycena citricolor (Berk. & M.A. Curtis) Sacc., but this species differs in forming a yellow stipe, slightly smaller basidiospores and the hyphae of the pileipellis are embedded in a gelatinous matrix. Mycena ixoxantha Singer, a species described from Colombia with citrine yellow pileus and amber coloured stipe differs in forming gelatinous pileipellis tissue.