Isotoma fluviatilis subsp. australis

Mat-forming, glabrous to sparsely and minutely pubescent perennial, rooting at nodes. Leaves oblanceolate to elliptic or obovate, 2–15 mm long, 1–7 mm wide, obtuse to acute, margins subentire to toothed; petiole 0–2.5 mm long. Flowers solitary in axils, irregularly spaced, bisexual, rarely female; pedicels 3–50(–85) mm long, glabrous or minutely pubescent. Calyx-lobes 0.9–2.5 mm long; corolla 6.5–15 mm long, almost white to intense blue or mauvish-blue, lobes sub-equal or the upper 2 slightly more deeply cleft, lanceolate to oblanceolate, 2.5–9(–11) mm long, 0.8–3 mm wide, tube 3–7 mm long, shortly slit; filaments 4–8 mm long, anther tube 1.3–2.5 mm long, seta of lower anthers 0.4–0.5 mm long. Capsule c. obovoid, slightly compressed, 2.5–7 mm long, seeds broadly ellipsoid, slightly compressed, 0.4–0.5 mm long, light brown to brown, weakly and irregularly reticulate.  Flowers Sep.–Jun.; fruits Oct.–Jul.