The pools here are from the nearby river, which must have recently gotten high enough to bring water as far inland as 50 yards or more. If the pools have been there longer than the Coprinellus has been fruiting — which, given the ephemerality of the former Coprinaceae, could mean anything over a day (or less?) — there appears to be a distinct possibility that a good many of these actually grew to maturity underwater. It was a bit treacherous getting close to the most “aquatic” fruit bodies (сава and I each almost took a dip), but those which could be retrieved appeared to be in fine shape despite being fully or partly submerged.

@ Alan:

Only the faintest of flecks could be seen on even the youngest of fruit bodies, causing us to consider ruling out C. micaceus, but I agree that it’s the most likely name. Maybe all the sloshing around could account for a shortage of flecks.