Epiphytes of the Sea Grass, Thalassia Testudinum, in Florida

One hundred and thirteen species of algae are reported occurring as epiphytes on the seagrass, Thalassia testudinum, 92 of which have been recorded from the south Florida area, 20 to 25 per cent of the total algal flora. Two groups of epiphytes are recognized, the year-around species and the seasonal annuals. Among the former are calcareous Corallinaceae which contribute significantly to the sediments of sea grass beds; among the latter is a group of large plants which may become sufficiently abundant during winter and spring to shade the Thalassia significantly. Each species listed is annotated, and a key to the species known to occur as epiphytes on Thalassia in south Florida is provided. Stictyosiphon sub-simplex and Polysiphonia harveyi are newly reported for Florida; Griffithsia barbata is newly reported for the Bahamas.