Halophila
Sea Wrack
5 species native Aust.; all states and territories
Submerged marine herbs with a creeping stem. Leaves opposite, oblong to elliptic or oblong-lanceolate, nearly transparent, 2–7 cm long with one central vein an intramarginal vein and very oblique lateral veins; stipules broad. Flowers small, unisexual, within a 2-leaved sessile axillary spathe. Male flowers pedicellate, emerging from the spathe; the female flower sessile, enclosed. Fruit ovoid, membranous, c. 10 mm long. Reproductive parts rarely seen.