Seagrape

“Coccoloba uvifera is a species of tree and flowering plant in the buckwheat family, Polygonaceae, that is native to coastal beaches throughout tropical America and the Caribbean, including central & southern Florida, the Bahamas, the Greater and Lesser Antilles, and Bermuda. Common names include seagrape and baygrape.

In late summer, it bears green fruit, about 2 cm (0.79 in) diameter, in large, grape-like clusters.The fruit gradually ripens to a purplish color. Each contains a large pit that constitutes most of the volume of the fruit.”

Wikipedia