Stems branching, slightly stouter than in G. submersum, forming masses up to ± 15 cm. diam., branches ± ascending at tips. Lvs opp., petioled, 3-7 mm. long, narrow-spathulate to narrow-obovate, obtuse, entire, membr., gradually narrowed into petiole ± = lamina, often elongating at fruiting period. Fls c. 2.5-3·5 mm. diam.; calyx subcampanulate, obtusely (3)-4-lobed. Corolla very small, white, pilose to very nearly glab., margins ± ciliate; upper lip 2-lobed, lower (slightly larger) 3-lobed. Stamens 4, not exserted. Stigma large, spathulate, irritable. Capsule small, ovoid-globose.

2n = 10

n = 5