In dense vegetation in full sun on a rocky slope, plants were declining but stiff and straight and had lost most of their seeds. This was found a couple weeks ago by Brett Trowbridge who shared the location with me. Massachusetts Natural Heritage should have probably been tracking this but we haven't been. It was listed as state historic in Cullina et al. 2011, (the county checklist) but there are 6 herbarium records since 2001 which could be checked. It's quite rare in New England though common further west and south. In fact this is the first iNat observation in New England. The strongly cup shaped tip of the upper glume is a dead giveaway for this. For more good photos, see Minnesota Wildflowers page on this.
on a muddy part of an otherwise clean pondshore. This is a non-native invasive species not well documented yet in New England. The last shot is not in focus. Had to grab it from a video. But is shows what it looks like from a distance.
Near a stream, very small (that's moss near it)
5 individuals observed adjacent the beach and nearby a saltmarsh. Knotty rhizomes and the axis of the inflorescence scabrous hispid.
At least a thousand plants around the edge. Shallow acidic coastal plain pond in Town of Plymouth near commercial cranberry bogs.
This is the first time iNat observation of this species in New England and New York. It's another coastal plain pond specialist. It's endangered in Connecticut and New Hampshire, threatened in Rhode Island, and does not occur in Maine. Thanks to the abundance of coastal plain ponds in Massachusetts it is only watch listed here and is common around some ponds, so not this one. I only found it in one location. In a shallow acidic coastal plain pond in Town of Plymouth near commercial cranberry bogs.