Pseudoclathrosphaerina spiralis J. A. Cooper 2005

Conidiophores and conidiogenesis unknown. Conidia 60–85 µm diam., hyaline to pale yellow, filaments 4 µm wide, septate, consistently dichotomously branching from a basal plate, branches inter-leaved, finally tapering into a layer of curved filaments enclosing the conidium core. Air-trapping. Pseudoclathrosphaerina was erected as a monotypic genus by Voglmayr (1997) for P. evamariae, an aero-aquatic fungus isolated from leaves and known from the USA and Austria. The genus is distinguished from Clathrosphaerina because the terminal hyphae do not anastomose to form a clathrate structure and have a dichotomous, overlapping branching pattern arising from a cruciate basal plate. Voglmayr (2001) discussed the features of similar genera (excluding Nidulispora). The species described here agrees in morphology with Pseudoclathrosphaerina but differs from P. evamariae by the overall dimensions being considerably larger (P. evamariae 25–45 µm diam., and filament 2.5–3 µm), and the outer hyphae eventually becoming elongate and spirally curved to enclose the body. The monotypic genus Nidulispora was erected by Nawawi & Kuthubutheen (1990) for N. quadrifida. This similar fungus also develops from a small basal plate that develops dichotomously, terminating in elongated arms, but the developing branches do not overlap to form the pseudoclathrate structure characteristic of Pseudoclathrosphaerina. In addition the conidia in N. quadrifida are dematiaceous and smaller (32–52 × 40–60 µm). The outer spiral filaments of P. spiralis give it a superficial resemblance to the genus Spirosphaera.