Herpothallon rubrocinctum (Syn: Cryptothecia rubrocincta)

This is a lichen of deep shaded hammocks. The latter term is used in our area to refer to islands of broad leaf trees which are surrounded by totally different plant communities. The red border around this easily recognized lichen is called a prothallus. Many lichens have a prothalline margin but red is unusual. White or black are more common.