Plumularia tubacarpa Watson, 2000

Hydrorhiza a small knot of tubular stolons.

Stem 9 mm high, monosiphonic, slender, erect, internodes long, smooth, increasing slightly in diameter distally, nodes transverse, caulus slightly tumescent above node, nodes becoming fainter distally along stem.

Hydrocladia alternate, one to four, usually two on internode, given off from a long, slender upwardly directed apophysis on side of stem; apophysis with an oblique distal node and frequently a transverse septum behind node; hydrocladia directed upwards at an angle of c. 35° to internode, with up to 10 hydrothecae. Hydrocladial internodes all thecate, nodes strongly oblique, an incipient septum passing into internode between base of hydrotheca and mesial nematotheca.

Hydrotheca seated in middle of internode, deep cup shaped, adcauline wall entirely adnate, convex, abcauline wall contiguous at an angle of 20° with internode, straight to faintly sinuous, concave just behind margin; margin circular, rim slightly everted and inclined slightly to hydrocladial axis.

Nematothecae all same shape and size, bithalamic, moveable, basal chamber long, cup foreshortened on adcauline side; mesial inferior seated on a prominence of internode, standing erect, not reaching base of hydrotheca; lateral nematotheca inserted on a minute pedicel behind hydrothecal margin, extending well beyond hydrotheca. Cauline internodes with variable number of nematothecae, o ne in axil of apophysis, one beside apophysis, one halfway between hydrocladia and sometimes one at side of internode just above node.

Gonotheca long, tubular, pointing downward, inserted without pedicel on proximal side of apophysis in lower stem region, distal end domed, perisarc smooth.

Colour: Colourless.