These small brown mushrooms were fairly abundant in the exposed mud.
Cap 3.5 - 9 mm across. Stipe 3.3 - 3.7 cm long x 0.5 - 1 mm thick. Pileocystidia, cheilocystidia, caulocystidia lageniform. Spores (4.6) 4.7 - 5.5 x (2.3) 2.6 - 2.86 (2.9) µm, Q = (1.6) 1.7 - 2.2 (2.3), N = 9, Me = 5.1 x 2.7 µm.
Maybe..
Occurring in acidic fen near lake. With conifers and willow around. looks to be the same as https://www.inaturalist.org/observations/48286944
Not sure which one. Spores are what I usually see, but short for H. inflatula
~5x1µ