Spergularia salina? Grassy area enclosed by Flatbush Ave & curved southbound exit to Belt Pkwy south of Belt Pkwy, Brooklyn, NY. In rather poor soil sparsely covered by grass, near road.
Note: Rhoads & Block (2007, The Plants of Pennsylvania, 2nd ed) give Spergularia salina J. Presl & C. Presl as the valid name with S. marina (L.) Griseb. as a synonym, while Stace (2010, New Flora of the British Isles, 3rd ed) gives S. marina (L.) Besser as the valid name with S. salina J. & C. Presl as a synonym. Mitchell (1993, below) uses Spergularia salina J. & C. Presl as the valid name.
Two distinctive features of this plant are (a) the well developed and prominent sepals which equal or exceed the petals in length and (b) the distinctly fleshy & rather blunt-tipped leaves.
Mitchell, R.S. 1993. Portulacaceae through Caryophyllaceae of New York State. Contributions to a Flora of New York State XI. New York State Museum Bulletin No. 486. The University of the State of New York, Albany, New York. vi, 124 pp.