Oryza latifolia, a wild species of rice, aquatic emergent, tolerant of flooding, occurs on floodplains of the Pantanal wetland, mainly in the Paraguay River sub-region. The aim of this study was to describe aspects of the biology and phenology of O. latifolia in two areas (Serra do Amolar and Bracinho) along the Paraguay River, in the township of Corumbá (state of Mato Grosso do Sul). Five patches of wild rice were observed in each area. Twenty replicates of quadrats (1m x 1m) were randomly established monthly in each patch, and percent cover was estimated; fl owering, fruiting, production of dry inflorescence and water depth were monitored from December 2006 to November 2007. Percent cover is correlated with water level and day length in the plots, reaching up to 80% at flood time in both areas. Recruitment of seedlings occurs during the dry season only on the plot edges. The reproductive phase of the species is short and starts after the flood peak. This period is correlated with a set of environmental variables such as day length and water level. Dispersal occurs by barochory, hydrochory and ictiochory, at the onset of receding water, and seeds stay viable for five months up to the dry period.
floodplains; Oryza latifolia; Pantanal wetland; phenology; wild rice
