Facultative apomixis in Smilax fluminensis (Smilacaceae) was studied in two natural populations of Tangará da Serra - Mato Grosso State, Brazil. The species presents umbelliform inflorescences and inconspicous flowers. We evaluated the reproductive system of female and male individuals of S. fluminensis in three consecutive reproductive episodes, and the sex ratio between male and female individuals was balanced.The formation of fruits was recorded in the reproductive system in all treatments:Cross-pollination (82.16%), Open pollination (70.30%) and Apomixis (31.81%). Most fruits counted developed three seeds. The formation of fruit with four seeds was recorded in both forest fragments. Fruit with one seed was recorded in only one of the fragments and, for the apomictic treatment, that number was about two times higher compared to other treatments. The bees Halictus hesperus and Tetragona clavipes, visited flowers of both sexes, and were considered as pollinators due to their frequency and behavior. Apomixis facultative in S. fluminensis is an advantageous reproductive strategy, since ensures their reproduction in the absence of pollinators.
Entomophily; Reproductive system; Sex ratio
