Archaeobotany is the study of archaeological materials that illuminate relationships between humans and plants. Excavations on shipwreck sites often produce many waterlogged botanical remains, often of plants rarely found on terrestrial sites. Techniques for extracting these remains from the sand/shell matrix are described in the Procedures link below; analysis of finds of pomegranate seeds, skin and floral fragments on the Late Bronze Age ship at Uluburun, Turkey are presented in the 2003 article.
Procedures for recovering archaeobotanical remains from submerged sites http://www.adventurecorps.com/sadana/flotation.html
2003 C. Ward, Pomegranates in the late bronze age eastern Mediterranean, World Archaeology 34.3:529-41. [View PDF]