Spore surfaces may be hairy, rugose, smooth, spiny or warty. The seeds are subquadrate, rugose and glabrous. The tarsus is fuscous, and the mandibles are rugose. Possibly, this rugose brow ridge supported a keratinous or scaly structure for displays. The seeds are transversely rugose and measure between long. The seeds have elliptical line or depression and are wrinkled or rugose. The fruit is rugose (wrinkled), brown, and strongly aromatic. The rugose corals existed in solitary and colonial forms, and were also composed of calcite. The complex arrangement of septa is diagnostic of rugose corals. Hexagonaria is a genus of colonial rugose coral. The nasal crest side is very rugose with a series of bosses and swellings. Hexacorallia also include the significant extinct order of rugose corals. However, some species of rugose corals could form large colonies (e.g., "Lithostrotion"). However, there are some unusual examples of well-preserved aragonitic rugose corals in the Late Permian. They may have arisen from a rugose coral ancestor.