This study aimed to compare angiosperm species richness and composition between floodplain 'murundus' (FM) of Araguaia State Park (ASP) in one of Brazil´s largest floodplains. ASP is located in Novo Santo Antônio, Mato Grosso state, and is bordered on the east by the Araguaia River, and on the west by Das Mortes River. Intensive floristic inventories were made on 11 hectares, and adjacent areas, of FM distributed over ASP. Environmental studies were performed by in situ descriptions. The soils are deep, mineral hydromorphic plinthosols, imperfectly to poorly drained, with low permeability. A total of 318 species, 193 genera and 66 families were collected, and FM values ranged from 51 to 135 species, 42 to 107 genera and 27 to 52 families. Erythroxylum suberosum is a typical species of Brazilian FM, Curatella americana typical of Mato Grosso FM and Byrsonima cydoniifolia typical of the ASP. The physical and spatial distribution pattern of the "murundus" (earthmounds) may reflect the seasonal flood pulse, since the floristic composition of the FM varied between the areas under the influence of the rivers that border the park. This was the largest floristic inventory ever undertaken in FM, with a significant increase in our knowledge and recording of typical species of the Cerrado Biome which occur in this phytophysiognomy.
Araguaia Floodplain; flooding; grassland; Erythroxylum suberosum
