Callitriche umbonata

Mostly aquatic but possibly also amphibious. Leaves dimorphic; lower leaves linear, 5–20 mm long, 0.5–1 mm wide, 1- or sometimes 3-veined, emarginate; upper leaves spathulate, 5–7 mm long, 1–3 mm wide, 3–5-veined, petiolate, rosetted. Flowers in lower axils solitary, female; flowers in upper axils paired, male and female together; bracteoles narrow-ovate, c. 1 mm long, membranous, persistent; stamen much longer than fruit; styles erect, c. 1.5 mm long, deciduous. Fruit more or less circular, 0.8–1 mm long and wide, subsessile, not thickened at base, dark brown; wing obscure. Flowers and fruits Sep.–Dec. (few records).