ABSTRACT
Piedraia hortae colonies are slow growing, small, folded, velvety, dark brown to black in color; reverse is black. Colonies may produce a reddish brown diffusible pigment and remain glabrous or covered with short aerial hyphae. Hyphae are septate, darkly pigmented, with intercalary chlamydoconidium-like cells. Ascostromata are pseudoparenchymatous structures of subglobose to irregular shape and black in color, with each ascostromata usually containing a single ascus. Asci (with readily dissolvable walls) are ellipsoid, solitary, or in clusters and contain eight ascospores. Ascospores (30-45 μm × 5.5-10 μm) are hyaline to darkly pigmented, one celled (aseptate), fusoid, curved, and tapering toward both ends to form the typical whip-like appendages. P. hortae is one of only a few pathogenic human fungi that generate sexual spores in its parasitic phase [3,4]. Piedraia quintanilhae differs from Piedraia hortae morphologically in that its ascospores do not have appendages [5].
