RESUMO -Foram estudados os possfveis sistemas de reprodu~iio em Dichorisandra thyrsiflora. A esp6cie parece ser predominantemente de fecunda~o cruzada. embora sem urn sistema de autoincompatibilidade definido. Conseqiientemente a autofecund~iio ocoere numa freqiimcia bern menor. Quanto a agamospermia. nenhum fruto foi observado em flores niio polinizadas.Os agentes polinizadores. invariavelmente. sao insetos do genero Bombus. Observou-se que o numero cromossomico da especie e 2n = 38. A analise da microsporogenese mostrou que a meiose e normal com exc~iio de algumas ct!lulas maes de p6len nas quais foi observada a for~iio de pontes cromatinicas em anafases I e II. sugerindo exist&tcia na popula~iio de heterozigotos para inversao . A form~iio de tetrades normais foi de 95% e a viabilidade dos griios de p6len foi alta. 87.2%. Palavras-<:haves: Plantas Ornamentais-Biologia da Reprodu~iio. Dichorisandra thyrsiflora-Commelinaceae. Microsporogenese.ABSTRACI' -(Aspects of breeding system of Dichorisancha thyrsijlora Mikan.) The breeding system of Dichorisandra thyrsiflora was studied. It was found that this is a mainly cross-pollinated species (92%). without a well defined self-incompatibility mechanism. Self-pollination was obtained in 27% of the analysed flowers. and apomixis was not observed. Pollination agents were mainly of the Bombus genus. The chromosome number of the species was 2n = 38. Microsporogenesis analysis showed normal meiosis. with only a few exceptions. in which chromatic bridges formation was observed in the anaphase I and n. suggesting heterozygosity for the inversion. Normal tetrad formation was 95% and pollen viability was high (87.2%).