Penidiella Crous & U. Braun, in Crous et al., Stud. Mycol. 58: 17 (2007).
Saprobic on hosts. Sexual morph: Unknown. Asexual morph: Mycelium consisting of branched, septate, smooth to verruculose, sub hyaline to pale brown hyphae. Conidiophores macronematous, occasionally also with some micronematous conidiophores; macronematous conidiophores arising from superficial mycelium or stromata, solitary, fasciculate or in synnemata, erect, brown, thin- to thick-walled, smooth to finely verruculose; terminally penicillate, branched terminal part consisting of a conidiogenous apparatus composed of a series of conidiogenous cells and/or ramoconidia. Conidiogenous cells integrated, terminal, intercalary or pleurogenous, unbranched, pale to medium brown, smooth to finely verruculose, tapering to a flattened or rounded apical region or tips slightly inflated, polyblastic, sympodial, giving rise to a single or several sets of ramoconidia on different levels; with relatively few conidiogenous loci, 1–3(–4), terminal or subterminal, subdenticulate, denticle-like loci usually conical, terminally truncate, usually unthickened or at most very slightly thickened, not to slightly darkened or somewhat refractive. Conidia in branched acropetal chains. Ramoconidia 0–1-septate, pale to medium brown, smooth to verruculose, thin-walled, ellipsoidal, obovoid, fusiform, subcylindrical to obclavate; conidia subcylindrical, fusiform to ellipsoid-ovoid, 0–1-septate, pale olivaceous to brown, smooth to verruculose, thin-walled, catenate; hila truncate, unthickened or almost so, barely to somewhat darkened-refractive (Adapted from Crous et al. 2007).
Type species: Penidiella columbiana Crous & U. Braun
Notes: According to Crous et al. (2007), Penidiella is phylogenetically closely related to Periconiella and Ramichloridium and share similar characters such as brown, macronematous conidiophores with similar conidial scars. However, Penidiella differs from Ramichloridium in lacking a prominent rachis which gives rise to solitary conidia and differs from Periconiella in having a unique branching pattern. Penidiella has a quite distinct branching structure, which consist of a single terminal conidiogenous cell which give rise to numerous ramoconidia that form secondary ramoconidia or the branched apparatus comprises numerous terminal and occasionally lateral conidiogenous cells which gives rise to series of ramoconidia. The branched apparatus is described as loose to dense, metula-like. The conidiogenous cells are fewer in number, generally 1–3(–4), with terminal or subterminal subdenticulate loci, and ramoconidia are conspicuous and abundant which gives rise to branched chains of secondary conidia with flat-tipped hila. Penidiella also resembles Pleurotheciopsis but differs in that the latter has unbranched, seldom percurrently multiplying conidiophores, lacking ramoconidia and colorless conidia formed in simple chains. Phylogenetically, Penidiella is a distinct genus in Microthyriaceae and can be differentiated from similar genera based on DNA sequence data. Molecular markers available for Penidiella are ITS, LSU, SSU, Actin, BTUB, Calmodulin, RPB2 and TEF-1.