Crassula aquatica (L.) Schönl.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Branching annual, rooting at the base, 2–10 cm; lvs linear, 3–6(–8) mm, spreading, connate around the stem; fls subsessile, solitary in the axils, mostly 4-merous, ca 1 mm wide, the pet white, erect or slightly spreading; seeds numerous; 2n=42. Muddy shores near the coast, usually in the intertidal zone; Nf. and Que. to Md.; Minn.; also La. to Tex., and on the Pacific coast and in Eurasia. Late summer. (Tillaea a.)