Corallum very crowded arborescent clumps of stems, branches and branchlets. Stem presumably oblique so lower and upper surfaces distinguishable; heavy, 3.5 cm diameter, closely divided into heavy gradually tapering branches. One branch: 15.5 cm long, 2 cm diameter at base, subdivided. Branches have abundant short branchlets all around but those on lower side less abundant. Branchlets on lower side almost vertical; long ones fewer on proximal region than towards apical region; simple, nonproliferous ones up to 1.3 cm high, slightly tapering to rounded or conical tips; several proliferous ones; proximal ones more terete than distal because radial corallites less prominent on former. Branchlets on upper surface crowded, rough sided because of prominent radials; tapering into acute tips; most bear branchlets. One simple unbranched branchlet 1.3 high, 6-8 mm across at base.

Axial corallite cylindrical, 2.5-3 mm across, 1-1.5 m exsert; wall thick, dense; calice around 1 mm diameter. Septa in 2 complete cycles, well developed; primaries reaching half radius points, directives only slightly differentiated; secondaries half as wide.

Axial corallites 3 mm across, very slightly exsert; wall moderately thick, very porous. Radial corallites on upper surface of various heights and diameters, crowed, mixed together. Height ranging from even with surface but for a low ring circumscribing calice to 3-3.5 mm, the latter just below apex of branches where they are tallest. Diameter ranges from 0.6 for lowest corallites to slightly over 1 mm across mouth of tallest one. Prominent corallites perpendicular to surface, tall ones towards apex slightly appressed but appear vertical being reflexed; spout-shaped, dimidiate; distal wall slightly above general surface, lower wall very high, thin or slightly thickened at edge; distinctly costate, very porous. Lower lip of smaller radials ligulate or acuminate oriented in any direction. Corallites on lower surface distant, subimmersed or plush with surface so this side appears smooth; some corallites obsolescent..

Radials on stem and proximal portions of branches all immersed or at most with a very slight ring around, less than a mm diameter; towards distal regions, some produce triangular or ligulate lower lips, mixed with bigger dimidiate ones with truncate tips near the apical parts, but still with few immersed corallites scattered among them; of various sizes. Radials on branchlets labellate or dimidiate, spout-shaped, wall slightly thickened, standing around 45° to branchlets, decreasing in diameter and height from base to apex, edge truncate. Large dimidiate basal corallite 3 mm high, 2 mm across semicircular edge. Several tubular proliferous corallites formed at sides of branchlets. Septa in one cycle, well developed; very occasionally 1 or 2 very narrow secondaries present; primary cycle not complete in few radials.

Intercalicinal areas spongy, reticulate, bearing simple scatterd low spines. Calicinal wall very distinctly costate; in some corallites edge of costae at base cut into very fine teeth.

Remarks: This coral undoubtedly belongs to the polymorphagroup by its numerous short lateral proliferations. However its heavy branches, the shape and position of its radial corallites and their septa distinguish it from A. polymorpha. It is quite close to A. forskali (Ehrenberg) but for heavier stems and branches, thicker wall and absence of verruciform radials.

Source: Nemenzo F (1967) Systematic studies on Philippine shallow water scleractinians: VI. Suborder Astrocoeniida (Montipora and Acropora). Part I - Text. Nat. Appli. Sci. Bull. 20 (1- 2): 1-141.