A survey of weeds growing in rice crops in the State of São Paulo was conducted. The life cycle, size, phenology and mode of reproduction of each of the collected species were studied. The herbaceous growth, annual life cycle, blooming and fructification during the warmest months of the ye ar and diss emination by seeds were mainly predominant for the studied species. From the six monocoty ledoneous families observed with a to ta l of 26 identified species, three were quantitatively more important: Gramineae, Cyperaceae and Commelinaceae. A taxonomical key was written for those genera with mo re than one species in an at tempt to help identification in the first growth stage. All the scientific and common names and when possible, the etimology of the genera species were included. In order to facilitate the keying and classification of seedlings from each of the studied specie s, a description and a drawing are provided.
Survey; weeds; rice; biology