A redescription of Plectosporium alismatis (hyphomycetes with glomerellaceous affinities)
Pitt, Wayne M.; Gams, Walter
Plectosporium alismatis (Oudem.) W.M. Pitt, W. Gams & U. Braun (syn. Rhynchosporium alismatis, Spermosporina alismatis), a pathogen of Alismataceae, is described in detail and delimited from the generic type, Plectosporium tabacinum, anamorph of Plectosphaerella cucumerina. The species is characterised by rather slow-growing, initially whitish but later orange-brown colonies, producing slightly curved, 1-septate, hyaline phialoconidia with granular contents. It is described for the first time from cultures. Most morphological features that apply to P. tabacinum, also apply to Plectosporium alismatis, but the conidia are more consistently 1-septate and more strongly curved. Additionally, cultures develop orange-brown pigmentation and chlamydospores are present. In both species little-differentiated appressoria are observed. The optimum temperature for growth of P. alismatis is higher (24-27°C) than in P. tabacinum (21-27°C) and some growth still occurs at 33°C.