Received for publication 1 Feb. 1988. Fla. Agr. Expt. Sta. Journal Series no. 8641. This project was supported in part from funds provided by the USDA-ARS Tropical and Subtropical Agriculture Grant and the Southwest Florida Water Management District. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.