Callitriche muelleri Sond.

Sonder, O.W. (1856) Linnaea 28(2): 229. Type: Lectotype: Victoria. Latrobe River, April or May 1853, F.Mueller s.n. (lecto [here chosen]: MEL 2289178, ex herb. Sonder; isolecto: K 000348666, MEL 2289180 & 2289179A).

Mat-forming herb.

Leaves orbicular to rhomboidal. Leaf blade 1.4-2.9 x 1.4-3.3 mm; petiole 1-3.1 mm long, as long or slightly shorter than the leaf blade.

Flowers sessile, about 0.3 mm diameter. One staminate and one pistillate flower in the same leaf axil. Female flower with 2 carpels. Filaments 0.1-0.2 mm long, anthers yellow. Styles 0.1-0.2 mm long, persistent.

Fruit breaking up into 4 one seeded mericarps. Wing of mericarp transparent. Nutlet about 0.5 mm diameter excluding the narrow wing. Wetted seeds sticky.

Occurs in the Atherton Tablelands region of NEQ, and in near coastal areas of southern Queensland and southwards to NSW and VIC, and in New Zealand. Altitudinal range in NEQ from 900m to 1150m. Grows in moist places and in creeks, in rainforest and sclerophyll forest.

Diagnostic features are the large wing of the fruit, and the bright green, orbicular leaves. Bean (2007).