According to Gerhardt (1996), Panaeolus rubricaulis is a rare Asian, apparently warm-loving species known from India, Sri Lanka, New Guinea and Vietnam. The spores are smooth and similar in appearance to those of Panaeolus cyanescens. It also has obvious pleurocystidia of the chrysocystidia type. Considering these features, Panaeolus rubricaulis is a very poor match for Mikael’s temperate collection.