Mushroomexpert.com says
The traditional genus "Psathyrella" is headed for some pretty big changes-…... Psathyrella is still a fairly large genus of saprobic gilled mushrooms with dark spore prints (ranging from brown to black or dark purplish gray),
"snap-able" stems,
and frequently hygrophanous caps
(meaning the caps often change color dramatically as they lose moisture, sometimes resulting in two-toned specimens).

The gills are neither mottled, nor do they dissolve into black goo when mature.

Under the microscope, species of Psathyrellahave spores that are brown or dark gray when mounted in KOH and feature smooth walls, as well as an apical pore. The pileipellis is hymeniform or "cellular."

The border line between Psathyrella andPanaeolus has always been confusing, even before contemporary DNA studies