Lytocarpia delicatula (Busk, 1852)

Hydrorhiza knotted; stems to 35 mm high, plumose, monosiphonic, unbranched, narrowing distally, prosegment ahydrocladiate, with strong distal hinge joint; stem thereafter hydrocladiate.

Hydrocladia frontal on stem, closely alternate, one on internode, cauline nodes transverse, indistinct or absent. Hydrocladial internodes short, nodes transverse, an intrathecal septum passing almost vertically downwards from posterior of hydrotheca to wall of internode opposite, a weak partial or complete septum passing from base of lateral nematotheca into internode.

Hydrotheca conical, adcauline wall flatly convex, adnate, abcauline wall convex; a strong septum passing from abcauline wall to base, connecting with intranodal septum; margin dentate with a fairly long mesial abcauline cusp, an indentation at base of cusp opposite mesial nematotheca; mesial abcauline cusp flanked by a pair of blunt cusps, followed a more rounded pair, a third very low pair and sometimes a fourth posterior pair reduced to an mere undulation.

Mesial nematotheca tubular, free part short, not reaching hydrothecal margin, terminal orifice circular to canaliculate, an elliptical secondary orifice connecting with hydrotheca at base of free part; lateral nematotheca tubular, a little tumescent distally, bent forward beyond hydrothecal margin , orifice circular, only slightly excavated on adcauline side. Cauline nematothecae more or less bean-shaped, with a single orifice, one in axil, one of similar size below, both facing outwards and one larger, above hydrocladium.

Colour: Stems brown, hydrocladia almost white.