Myxomycetes on Palm Trees: Species on Attalea speciosa Mart. ex Spreng

Attalea speciosa Mart. ex Spreng (babaçu) is a palm tree of considerable economic importance in Brazil, especially in the northeast portion of the country. The myxobiota of babaçu was studied by examining living and dead trunks, leaves, inflorescences and fallen fruits on the ground during the wet season at the Teresina Park, Piauí State, Brazil. Taxonomic diversity, species diversity, frequency of occurrence, abundance and constancy of each species were determined in two areas of deciduous mixed forest. The taxonomic diversity of the myxobiota was similar, with values of 1.5 and 1.6 for the two areas. The highest frequency of occurrence value was recorded for the spathe (50% 54%), followed by the petiole (18% 19%) and leaf sheath (4% 19%). Myxomycetes were absent on fallen fruits and rare on the leaf blade (6%) and dead (9%) or living (2%) trunks. Hemitrichia serpula (Scop.) Rostaf. ex Lister, Perichaena depressa Lib., Arcyria cinerea (Bull.) Pers. and H. calyculata (Speg.) M. L. Farr were the species characterized by the highest levels of constancy, abundance and frequency. Cribraria microcarpa (Schrad.) Pers. and Stemonitopsis typhina (F. H. Wigg.) Nann.-Bremek. were occasionally present. Ceratiomyxa fruticulosa (Mull.) T. Macbr., Clastoderma debaryanum A. Blytt, Craterium aureum (Schumach.) Rostaf. and Physarum melleum (Berk. & Broome) Massee were infrequently encountered. Other species recorded were Arcyria denudata (L.) Wettst., Cribraria cancellata (Batsch.) Nann.-Bremek., C. violacea Rex, Lycogala exiguum Morgan, Metatrichia vesparia (Batsch) Nann.-Bremek. ex G. W. Martin, Physarum bogoriense Racib., P. nucleatum Rex, P. pusillum (Berk. & M. A. Curtis) G. Lister and Stemonitis axifera (Bull.) T. Macbr. The myxobiota of the shaded study area was characterized by a higher diversity (6.10) than the unshaded area (2.10), and the incidence of myxomycetes on the A. speciosa trees selected for study was appreciably higher (100% and 40%, respectively).