Symplectoscyphus sibogae (Billard, 1924)

Stolon thick-walled, tubular. Stem 4 mm high, straight, with 5 alternate hydrothecae, an indistinct transverse basal node between hydrorhiza and first hydrotheca; no other obvious nodes.

Hydrothecae large, tubular, arching outwards from stem, narrowing to margin, adnate adcauline wall short, parallel with internode, free adcauline wall weakly convex to almost straight, abcauline wall contiguous with border of internode, faintly concave; floor of hydrotheca narrow, transverse to internodal axis. Margin everted with 3 fairly sharp cusps with shallow embayments between; a large internal submarginal cusp at base of each embayment; operculum of 3 delicate triangular valves.

Perisarc thick and smooth throughout; opercular valves thick.

Colour white.