Based on the plant list for Salt Point, if these are in the Araceae family, the only species in that family found here is Calla Lily. I don't know about these because not a single one was starting to flower. Some Several feet high already. There were so many of them coming up in one spot along a marshy area along a seasonal creek amongst deer fern.
~2' across, near the river
Perhaps same as https://www.inaturalist.org/observations/74423959