Monotheca obliqua (Johnston, 1847) [Invalid]

Stems simple, up to 5 mm high, arising at regular intervals from a creeping hydrorhiza. Stems bearing alternate simple, short hydrocladia given off in one plane. Stem internodes with two, two-chambered nematothecae, one in the axil of the hydrocladium and one about halfway along the internode.

Hydrocladium short, beginning with an athecate internode without hydrothecae or nematothecae followed by a distal internode with a terminal hydrotheca. Hydrotheca bell-shaped, base adnate to the hydrocladium, margin facing forward, slightly convex. Hydrothecate internode with one, two-chambered nematotheca behind the hydro theca and two, two-chambered nematothecae side by side, in front of the hydrothecal margin.

Gonotheca very large compared with colony size, borne on a short pedicel low on the stem, conical, expanding distally, truncated at the top, containing a single planula larva.

Colour: colonies white to straw-coloured, gonotheca usually light brown.