From December, 1994 to September, 1995, seven collecting trips (2-4 days each) were carried out in the "Parque Nacional de Sete Cidades" (4º5'-4º15'S, 41º30"-41º40'W, 450m alt.), Piripiri, Piauí State, Brazil, in order to collect Myxomycetes fruiting bodies on carnauba palm trees (Coperniciaprunifera (Miller) H. E. Moore), established in a place called "Lagoa Seca" (savanna-like stunted vegetation). The samples were herborized and included in the UFP Herbarium (Universidade Federal de Pernambuco, Recife, PE) and the TEPB Herbarium (Universidade Federal do Piauí, Teresina, PI). In relation to the substrate, the "carnaubeira" showed a high incidence of Myxomycetes (70%) on living stipitis and dead leaves. Sixteen species belonging to Ceratiomyxaceae (Ceratiomyxa lsp.), Didymiaceae (Diachea lsp., Didymium 2spp.), Physaraceae (Craterium lsp., Physarum 4spp.), Trichiaceae (Arcyria 2spp.) and Stemonitaceae (Comatricha 3spp., Macbrideola lsp., Stemonitis lsp.), were registered. Ceratiomyxaceae, represented by Ceratiomyxa fruticulosa (Mull.) Macbr., is a new record for Piauí State.
Myxomycetes; Arecaceae; Copernicia