Aquatic or terrestrial, mat-forming perennial, leaves and calyx sometimes sparsely hairy with eglandular hairs. Leaves 6–20 mm long; lamina obovate to elliptic, 3–16 mm long, 1–3 mm wide, 0.5–2.5 times longer and 2–6 times broader than petiole, base gradually or abruptly narrowed into petiole, green, midrib apparent on lower surface; petiole 2–10 mm long, often whitish. Pedicels erect, 1–12 mm long. Calyx 1.5–2.3 mm long, green, 4-toothed, 2 teeth larger; corolla 2-lipped, white to pale blue, lobes 5, 1–1.5 mm long, ciliate; stamens 4; stigmatic lobe broad. Flowers Dec.–May.
LoM, MuM, Wim, GleP, VVP, VRiv, MSB, RobP, MuF, GipP, OtP, Gold, CVU, DunT, NIS, EGL, EGU, HSF, HNF, MonT, VAlp. Also SA, NSW, Tas. New Zealand. Widespread on clayey or silty soils on river flats, lake margins, beside freshwater swamps, seasonally inundated depressions etc.
