Piedraia Fonseca & Leão, Mem. Inst. Oswaldo Cruz 4 (Suppl.): 125 (1928).
Pathogen of human hair. Sexual morph: Ascostromata consisting of pseodoparenchymatic tissue, scattered singly on the underlying part of primate hairs, variable in shape and size, but usually flat, elongated with a rough surface, dark in colour, multi-loculate in section, containing numerous cavities, irregularly distributed throughout. Each locule becomes erumpent as the asci mature, and can be seen as small dimple, and contains a single ascus. Pseudostiolate locules, without pseudoparaphyses, with paraphysoids. Asci 8-spored, bitunicate, subglobose to broadly ellipsoidal. Ascospores 1-celled, hyaline, rarely light yellowish or greenish, without septa, thin-walled, fusiform, curved, more or less straight to falcate, tapering toward both ends, with tapering gelatinous appendages or without appendages. Germination by several germ tubes. Asexual morph: Undetermined (Adapted from Hyde et al. 2013).
Type species: Piedraia hortae Fonseca & Leão
Notes: Piedraia is a filamentous fungus that causes infection of hairs and forms hard nodes on hair shafts. The infection results in development of asymptomatic brown to black nodules which comprise ascostromata enclosing asci and aseptate ascospores. Piedraia is a well distinct genus accommodated in its own family Piedraiaceae. Molecular markers available for Piedraia are LSU, SSU, ITS and RPB2.