is a Rhodophycean alga with wide distribution throughout the tropics and subtropics (Kilar and McLachlan, 1986). It occurs on a wide variety of substrata, from hard bottom, as an epiphyte on other algae, or as a free living drift alga. It is often a large component of drift algae biomass. A. spicifera
has a large, irregularly shaped holdfast for attachment to hard bottoms. From the holdfast, erect fronds begin to branch out. The main branches have short, determinate branchlets that are irregularly shaped and spinose. Branchlets are hook-like, brittle and fragment easily under heavy wave action. Color is highly variable, and can be shades of red, purple, or brown (Littler and Littler, 1989). A. spicifera
grows upright to approximately 25 cm.