Annotated Checklist of the Flowering Plants of South Padre Island, Texas

Abstract

This study catalogues the flowering plants of South Padre Island, Texas. A total of 207 species in 47 families is listed. The abundance and ecological distribution of each taxon are noted. Comparisons are made with the flora of Mustang Island, Texas. Ninety-three species, 96 genera and 36 families are common to both islands. Three families, Compositae, Gramineae and Leguminosae, contain large shares of the total number of species on both islands. Apparently, much of the floral diversity is due to the presence of a large number of species that are represented by small populations. Padre Island is a barrier island that extends approximately 182 km along the gulf coast of Texas (Fig. 1). It varies in width from 450 m to 5 km and is separated from the Texas mainland by the Laguna Madre. Padre Island National Seashore occupies most of the northern and central portion of the island and extends southward to the Port Mansfield Cut. That portion of Padre Island which extends from the Port Mansfield Cut to the Brazos-Santiago Pass at Port Isabel is referred to as South Padre Island (Judd 1976). Except for small holdings at the northern and southern ends, South Padre Island is under private ownership and subject to development. Presently development is limited to the southernmost 8 km of the island, but Park Road 100 extends 11 km further north and provides access roads to the beach. Study of the flora and vegetation of the Texas-Mexico barrier island system is limited and most investigation has been directed to North Padre Island and Mustang Island (Jones et al. 1961; Whitehouse 1962; Gould and Box 1965; Jones 1975; Rabalais 1975; Gillespie 1976). Poggie (1963) studied the vegetation of the foreshore zone of the barrier island off the coast of the Mexican state of Vera Cruz. Gonzalez-Medrano (1972) listed common species located around the Laguna Madre in Tamaulipas, including species typically found on the coastal dunes. Selander et al. (1962) included a brief discussion of the