Aquatic herb. Stolons up to 1 m. long or more, terete, smooth and glabrous; internodes 3–10(–15) mm. Leaves very numerous, digitately divided into 3–6 primary segments and usually auricled at the base; primary segments 2–6 cm. long, ± lanceolate in outline, pinnately divided, the rhachis filiform or ± inflated and up to 2 mm. thick; pinnae repeatedly dichotomously forked; ultimate segments capillary, minutely setulose; auricles when present reniform or orbicular, up to 10 mm. long, margin usually denticulate or ± divided into setulose capillary segments. Floats verticillate or sub-verticillate on the lower half of the scape, 3–10, inflated, narrowly cylindrical to fusiform, 2–5 cm. long, bearing a variable number of reduced or sometimes well-developed leaf-segments at the apex. Traps usually numerous, lateral near the base of the ultimate and penultimate leaf-segments, broadly ovoid, shortly stalked, 1–3 mm. long; mouth lateral; upper lip naked or with 2 short simple or sparsely branched hairs; lower lip naked or with a few shorter simple hairs. Inflorescence erect, lateral, 3–20 cm. high; flowers 2–15, congested at anthesis; inflorescence-axis elongating in fruit; scape filiform to relatively stout, straight, smooth and glabrous; scales absent; bracts basifixed, ovate, 1–2 mm. long; bracteoles absent; pedicels filiform, erect or spreading at anthesis, 1.5–5 mm. long, strongly reflexed and thickened in fruit. Calyx-lobes subequal, broadly ovate, apex rounded or lower sometimes emarginate, ± 3 mm. long at anthesis, strongly accrescent, becoming fleshy, up to 10 mm. long and enclosing the capsule. Corolla white or yellow, usually variously marked with red or purple lines, 7–10 mm. long, ± densely covered externally with glandular hairs; upper lip broadly ovate, 1.5–2 times as long as the upper calyx-lobe, apex truncate or emarginate; lower lip orbicular, apex rounded or emarginate; palate raised, bigibbous; spur cylindrical, ± as long as the lower lip; filaments linear, dilated above; anther-thecae subdistinct. Ovary globose, minutely squamulate; style distinct, as long as the ovary; stigma lower lip semi-orbicular, upper obsolete. Capsule globose, circumscissile, ± 5 mm. in diameter with the style often considerably elongated. Seeds numerous, prismatic, 4–6-angled, ± as wide as high, ± winged on the angles, hilum prominent; testa-cells distinct, elongated, ± 0.05 mm. long.