... I believe the top photo of the plant in the middle of the rush stems looks to be Arrowhead. The scape (stem with flowers) has the tell-tale triple pedal flower and below that are the achenes (seed pods).
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Might be. The leaves do not look like the arrowhead we have a round here (they look like arrowheads) but I think there is a lance leaf variety that looks similar to the picture. Water Plantain has similar flowers , etc.