| Corallum morphology in Siderastrea (according to Wood. 1983) | ||||
| Genus | Form and size of colony | Calice arrangement | Walls/collines | Septal and septocostal arrangements and features |
| Siderastrea | Small massive or encrusting colonies. | Rounded and regular; 2-4mm in diameter | Walls shared, wide and often with midline. | Numerous and in cycles; 35-45 in a calice 3mm in diameter; margins with small either simple or dentate spines; synapticulae present; septa often fuse; septa perforated. |
| Pseudosiderastrea | Encrusting or massive colonies usually less than 10cm in diameter. | Rounded irregular or angular; 2-4mm in diameter. | Shared wall a narrow ridge, no midline; calice wide and shallow. | Septa in cycles, usually about 30 in calice 3mm in diameter, up to 48 in larger calices; margins with small dentate spines; synapticulae present; septa often fuse in calices; septa rarely perforated. |
| Anomastrea | Encrusting or massive, usually less than 10cm in diameter. | Rounded, angular or irregular; 2-4mm in diameter. | Shared wall a narrow ridge, no midline; fossa wide and fairly deep. | About 30 septa in a calice 3mm in diameter; margins w/ small dentate spines; synapticular links rarely formed; fusion of septa in common; septa may be partially perforated. |
| Coscinaraea | Massive, encrusting or partly foliaceous; seldom larger than 30cm in diameter. | Rounded, irregular, elongate or in series; 2-7mm in diameter, or across valley. | High or low walls or collines around the calices; walls may be wide, but w/o a midline. | About 20-30 septa in a calice 3mm in diameter; margins with dentate spines; synapticulae present; occasional fusion of septa in calices; septa perforated. |
| Psammocora | Great variation in growth form and colony size. | Rounded, with indistinct outline; about 2mm in diameter. | No walls, but collines often enclose single or several calices. | Septa often branch and ramify, giving a petaloid appearance; seldom more than 10 reach the columella; margins with granular protuberances that are usually minutely branched; synapticular rings usually well develooped; septa do not fuse in calices. |