Common Name(s):Giant slit-pore sea rod, Nodding plexaurella
Colony Form:Colonies usually tall with few long branches in multiple planes; to 1.5 m tall.
Axis:Extensively mineralized by calcite, up to 85% mineral aggregate at branch tips; aggregates up to 5 mm in length and embedded longitudinally in the gorgonin (Lewis et al. 1992).
Branches:Sparse, dichotomous; terminal branches 10-15 mm across and up to 1 m long; tips usually somewhat enlarged or bulbous.
Apertures:Distinctly slit-shaped apertures; calices form widely separated hemispherical mounds.
Mucus:None.
Color:Tan, light brown to mauve; putty-gray or light brown in alcohol.
Sclerites:Polyp armature: strong; blunt rods to 0.3 mm long. Axial layer: spindles, crosses and capstans, the latter often with two longer rays, 0.15-0.25 mm long. Middle layer: large, slender spindles, triradiates, 4-radiates, to 0.45 mm across. Surface layer: capstans usually with two longer rays, 0.075-0.2 mm across.