Psathyrella: spores purple-brown to black; stature typically collybioid to galerinoid; pileus dry, splits radially with ease and is very fragile; the stipe breaks easily and is very fragile. You need to refer to the chart on page 119 of Mushroom I which provides features with which Psathyrella can be distinguished from Panaeolus, Panaeolina, Psilocybe, or Stropharia.

There are a large number of Psathyrella species and the species are variable in the size and shape of the fruiting bodies. There are about as many species of Psathyrella as all of the other 4 genera mentioned above.

The extreme fragility of the fruiting bodies is the most reliable of all macroscopic features.