FOSSIL FLORAL EVIDENCE OF MALPIGHIACEAE AND AN EARLY PLANT-POLLINATOR RELATIONSHIP

Fossil flowers with affinities to Malpighiaceae have been discovered in the Middle Eocene Claiborne formation of northwestern Tennessee. The new taxon Eoglandulosa warmanensis gen. et sp. nov. Taylor and Crepet, has paired glands on the five sepals, clawed petals and tricolporate pollen with reticulate ornamentation and an unusual infratectal wall structure of anastomosing elements. The fossil is similar in wall structure to some extant species of Malpighiaceae. Glandular floral morphology in extant species is associated with specific anthophorid bee pollinators and the fossil evidence suggests that such specific plant-pollinator relationships existed during the Eocene. This fossil species also suggests that by the Eocene, South American floral elements had migrated to North America via island pathways, and that the Mississippi embayment was nearly frost-free.