Limosella

Marsh or aquatic, perennial herbs, tufted, creeping or floating; stemless or with stolons, rooting at nodes, glabrous. Leaves usually radical, sometimes fasciculate at nodes, rarely alternate, simple, usually petiolate, erect or floating, lamina linear, subulate, spathulate, oblong-ovate or suborbicular. Flowers usually solitary, axillary; pedicels ebracteolate, often deflexed in fruit. Calyx tubular, (4)5-lobed; tube funnel-shaped or campanulate; lobes subequal, usually shorter than tube, rarely longer. Corolla tubular, 5-lobed, subregular; tube campanulate or turbinate; limb erect or rotate; lobes subequal, posterior outside in bud, rounded, ovate or oblong, pilose on inner face. Stamens 4, mostly somewhat didynamous, in mouth of corolla tube or shortly exserted; filaments filiform, arising +/- in middle of corolla tube, filaments of lower stamens often crossing those immediately above them at right angles; anthers with 2 equal, confluent thecae. Ovary bilocular, at least near base, globose or elliptical; ovules many; style varying in length, terete, sometimes incurved, included or exserted; stigma capitate. Fruit an ovoid to +/- spherical capsule, almost indehiscent or at length loculicidal; valves entire. Seeds many, subglobose, 4-sided, or oblong; testa thin, brown, ribbed or reticulate. x = 10 (9-1 report) (polyploidy).