Halecium tabulatum Watson, 2005

Hydrorhizal stolons tubular, wrinkled, walls thick. Stems simple to robust and shrubby, some lightly fascicled basally by one or two accessory stolons extending a short distance upwards from hydrorhiza; stems thereafter monosiphonic, branched or unbranched; branch arising as a secondary hydrophore beside diaphragm of a hydrotheca; dichotomous branching often occurring from a hydrophore on each side of hydrotheca.

Hydrophores (pedicel) of variable length, the longest in lower stem region, arising from apophysis below hydrothecal diaphragm; hydrophore with a proximal fold and slight tumescence; typically one or two constrictions in proximal region, walls thereafter smooth, expanding to hydrotheca; hydrophores with up to four linear regenerations of variable length usually all shorter than primary.

Hydrotheca shallow, expanding to margin, rim circular, usually weakly everted, a row of large desmocytes below rim; diaphragm thick, horizontal, a distinct shelf in perisarc around perimeter; most hydrothecae with a deep bowl-shaped pseudodiaphragm below true diaphragm. Some hydrothecal margins replicated once or twice.

Hydranth large with ca. 24 tentacles.

Mature female gonotheca kidney-shaped (lateral view), compressed in posterior view, seated on a very short, slightly twisted pedicel on hydrophore below hydrotheca; young gonotheca inverted conical, mature gonotheca widest on concave side at level of aperture; at maturity aperture a deep slightly inwardly tilted shelf containing a reduced hydranth; immature gonophore with four or five spherical ova; one ovum remaining inside gonothecal aperture at maturity.

Perisarc of colony thick.

Colour: Colony white (preserved material).