Corallum light, consisting of fragile basal plate supporting at its central region a confused mass of vertical, coalescent stems. Plate radially pleated at margins but plane inward; up to 14 mm thick towards center, 2.5 mm at edge. Vertical stems 8 cm high near center, decreasing in height towards periphery; irregularly disposed. Branches adnate, close to each other, cylindrical, tapering, extensively coalescent; all directed upward, apices almost acute. Epitheca in patches, very limited extent.
Calicles very distinct except along periphery region of basal plate where they are usually oblique; diameter 0.75 mm; 2-4 diameters apart on plate; more distant on stems and branches; flush with surface or very slightly sunken. Those on undersurface smaller (0.5 mm across), inconspicuous being not sharply cut out from surrounding coenenchyme.
Septa nonlaminar series of curve spines, reaching slightly beyond mid radius points; directives indistinguishable. Secondaries small; complete cycle but often unequally developed, making septal organization asymmetrical. Loculi distinct, petaloid or heart-shaped; but not so on undersurface.
Intercalicinal reticulum distinct, lax on upper surface of basal plate, compact on undersurface; thread wider than meshes on columns, reverse is true on upper surface of plate. Tubercles bristly, somewhat evenly distributed; tall on stems (especially at tips) reduced to spines with fimbriated tips on basal plate; only fine spines on undersurface; towards tips of branchlets may be partially fused to produce ramparts around calicles.
This coral was first identified as M. hispida. The finding of C-1208 makes it necessary to distinguish it from the old species. The present species has slender tapering terminal branchlets, the septa are not as well organized although it has more, the tubercles are less numerous and reduced to mere spines on the basal plate, the corallum as a whole is more porous and consequently lighter than that of the old species.
C-234 which is considered belonging to this species has no basal plate. It might have been broken off from an extensive colony.
UP C-234:Puerto Galera Bay, Oriental Mindoro (collector and date not recorded)
