A bloom of Tympanicysta Balme (green algae of zygnematalean affinities) at the Permian-Triassic boundary

Filamentous microfossils Tympanicysta Balme, formerly interpreted as conidia of ascomycetes, are similar to zygnemataceous algae Spirogyra Link in the general morphology, folding of transverse septa, chloroplasts and akinetes. Their rise at about the Permian-Triassic boundary is, therefore, unrelated to the boundary "fungal event", but is rather a consequence of a Permian-Triassic widespread ponding and swamping of river systems at the initial stage of the end Permian transgression.