Glabrous aquatic; stems floating, filiform, branched. Lvs numerous, submerged, capillary, to c. 1 cm long, usually entire but occasionally dichotomous. Bladders 1-1.5 mm long when mature, obliquely ovoid, numerous, situated on the lvs, shortly stalked; mouth with 2-3 long setae. Scape 3-20 cm long, slender, erect, 1-4-flowered; bracts c. 1 mm long, broad, membranous; pedicels to nearly 1.5 cm long, filiform. Calyx lobes 2.5-2.8 mm long, suborbicular. Corolla yellow; upper lip 7-10 mm long, ± suborbicular, narrower than lower lip, entire; lower lip 7-9 × 9-13 mm, entire, suborbicular, broader than long; palate pulvinate; spur 4-7 mm long, conic, with rounded apex. Filaments strongly curved, flattened. Ovary globose; stigma subsessile, with large, ± rounded lower lip. Capsule 2-3 mm diam., globose.