Common Name(s): Gray plexaurella, Gray sea rod
Colony Form: Colonies tall, bushy, dichotomously branched, with long thin branches arising near the base and through half-way up colony height.
Branches: Branches thin, straight, firm and stiff; 5-12 mm in diameter.
Apertures: Oval and pore-like, conspicuously open; mostly smooth, or with aperture margins slightly elevated; long axes of apertures oriented along branch.
Color: Light brown, beige, or grey.
Sclerites: Polyp armature: small flat rods 0.06 mm long. Axial layer: 6-radiates ~0.15 mm across, and some flattened rods. Middle layer: stout 6-radiates, some with two longer rays; also short-rayed, stubby butterfly sclerites. Surface layer: small 6-radiates, most with two rays slightly longer.
Habitat: Common on patch reefs and inshore, less common on deep reefs.
Distribution: South Florida, Bermuda and throughout the Caribbean Sea.
Notes: Most middle layer sclerites are 6-radiates with two arms more strongly developed; also some short-rayed, stubby butterfly sclerites (Bayer 1961). Preyed upon by the generalist octocoral predatory snail Cyphoma gibbosum, but also by Cyphoma signatum, a specialist predator on Plexaurella spp. (Ruesink and Harvell 1990).