Aquatic, floating submerged herbs. Stem (stolons) monomorphic, branched, up to 1.7-2.5 cm long, terete, glabrous. Leaves filiform usually with 2 primary segments, internodes 5-9 mm, pinnately divided; segments capillary, denticulate, bearing solitary or fasciculate setulae on each tooth. Bladders dimorphic, ovoid, stalked, 1.5-3 mm long, with simple forked antennae. Inflorescence erect, 8-20 cm long; peduncle filiform, terete, glabrous; scales 2-3, 1.9-3 mm long, ovate, basifixed, apex acute-obtuse. Bracts basifixed, c. 4 mm long, ovate, base auriculate. Flowers 4-12; pedicel filiform, terete, 10-15 mm long, erect, deflexed in fruits. Calyx lobes ± subequal, ovate. Corolla yellow, externally glabrous; upper lip ovate, apex refuse; lower lip darker with reddish brown lines and spots ± flat, reniform, margins spreading; palate glabrous; spur broadly conical at base, c. 6 mm, longer than wide, inner distal half with internal glands on both adaxial and abaxial surfaces. Filaments curved c. 2 mm long. Stigma upper lip short, lower lip semicircular, ciliate. Ovary globose, glandular. Seeds prismatic, 4-6-angled, narrowly winged.