ABSTRACT: During a revision of the genus in Argentina, two new species were found: H. austrocedri from the province of Chubut, and H. minutissima from the province of Buenos Aires. Both belong to subgenus Hohenbuehelia section Nigricans. In the present paper we describe and illustrate the two new species and compare them with H. singeri, H. nigra, H. bullulifera and H. unguicularis. In addition, we studied the holotype of H. pilitomaculoides, which we reduce to a synonym of H. nigra.

KEYWORDS: Agaricales, Hohenbuehelia austrocedri, H. minutissima, H. sect. Nigricans, systematics

NOMENCLATURAL NOVELTIES:
Hohenbuehelia austrocedri Fazio & Albertó, p. 118
Hohenbuehelia minutissima Fazio & Albertó, p. 120