Common Name(s): Porous sea rod, Porous false plexaura, Dry sea feather
Colony Form: Colony form Bushy; not in a single plane; ~0.2-2.5 m tall.
Branches: Crowded and ascending; long or stout; round and flexible, ~4-10 mm in diameter.
Apertures: Large, gaping, elliptical or oval and crowded, 0.15 mm across and larger; separated by less than their own diameter; arranged in weak spiral along branches. No protruding calices.
Mucus: Slimy branch tips.
Color: Living colonies light olive gray-brown to purple or greenish-yellow. Dries tan. In alcohol white or gray.
Sclerites: Polyp armature: none. Axial layer: deep purple capstans (0.1-0.15 mm), small spindles (0.2 mm and longer), and irregular sclerites (0.15 mm and larger). Outer layers: abundant colorless spindles 0.6-1.0 mm long, with prominent, widely spaced tubercles often developed as strong spines along one side, and large clubs to 0.4 mm long, grading into spindles with spines on one side. Spindles in deeper layers deep purple, often branched and forming 3- or 4-rayed sclerites.
Habitat: Most reefs, 0-49 m, most commonly 0-30 m. Bayer (1961) recorded it off Colombia in 283 m.
Distribution: Bahamas, South Florida, and Caribbean Sea.
Notes: Crowded apertures distinguish this species from P. flagellosa (Bayer, 1961). Flamingo tongue gastropods, Cyphoma spp., are common predators of P. porosa (Lasker et al., 1988).