Vaucheria (Xanthophyceae, Vaucheriaceae) of the Central Florida Gulf Coast

Vaucheria velutina, V. longicaulis, and V. litorea have been found in the greater Tampa Bay area of the Florida west coast, the latter two newly reported for Florida. They colonize a band of the intertidal zone principally from mean sea level or just below to below mean low water along low energy beaches between mangrove stands or salt marshes and the innermost edge of seagrass beds. All species appear by 1 November, forming dense mats that stabilize and promote further accumulation of fine sediments. They disappear between 15 April and 15 May. Culture experiments indicate that exposure to a temperature of 23°C or lower stimulates their appearance in the autumn. It is our opinion that Vaucheria, when apparently absent from May to October, is present in the form of dormant zygotes that were produced late in the previous growing season. Sediments stabilized and accumulated by Vaucheria during the cooler months are partially maintained by mat-forming bluegreen algae during the warmer months.