Isotoma tridens
(E.Wimm.) LammersMat-forming, glabrous or minutely pubescent perennial; stems often reddish, rooting at nodes. Leaves oblong-elliptic, 1.3–8 mm long, 0.5–3 mm wide, margins toothed (rarely c. entire), distal pair of teeth prominent, petiole 0–0.6 mm long. Pedicels 0.3–20 mm long, usually minutely pubescent. Hypanthium densely minutely pubescent; calyx-lobes 0.5–1.5 mm long; corolla 4–9.5 mm long, white or tinged very pale mauve, glabrous to sparsely and minutely pubescent externally, upper 2 lobes subequal to or slightly narrower than lower 3, c. elliptic, 2–5.5 mm long, 0.5–1.4 wide, tube 2–5 mm long, shortly split; filaments 2.8–5.3 mm long, anther tube 1–1.3 mm long, apical seta of 2 lower anthers c. 0.1–0.2 mm long. Fruit ellipsoid to globose, 1.5–3 mm long; seeds broadly ellipsoid, slightly compressed and angular, 0.3–0.4 mm long, light to dark brown, alveoles c. isodiametric. Flowers mostly Nov.–May; fruits Jan.–Jun.
VVP, VRiv, MuF, GipP, WaP, CVU, NIS, EGL, HSF, HNF. Occurs on lake and reservoir margins, and on the fringes of billabongs and creeks where the silty substrate bakes hard in summer. Possibly overlooked due to its diminutive stature and perhaps more widely distributed than records indicate. .
Plants apparently wither in fruit and remain dormant over winter (when plants are usually submerged) shooting again in warmer, drier conditions.
Albrecht, D.E.; Walsh, N.G. (1999). Campanulaceae. In: Walsh, N.G.; Entwisle, T.J., Flora of Victoria Vol. 4, Cornaceae to Asteraceae, pp. 553–553. Inkata Press, Melbourne.
