Growing in compacted clay/sand on an eroding cliff near the intertidal zone. There were quite a few large patches of the same material scattered along the cliffs.
Same material can be found here by @leahparr
https://www.inaturalist.org/observations/199712649
with comparison to Antitrichia californica. Both on Poplar.
on saturated sediment bank/roadcut
In rock crevice
Five individuals in this population. [Edit: photo of winged seeds added, 1mm scale.]