Fruits and seeds of Tipuana tipu were morphologically and anatomically analyzed during development. The origin of the pericarpic wing was elucidated and the hypothesis of the occurrence of polyembriony mentioned in literature was verified. Slides were prepared according to the conventional techniques. The fruit of Tipuana tipu is a typical samara. Its wing originates from the lateral and terminal regions of the ovary and from the lateral of the style. The wing can be already traced in young ovaries of floral buds. Bitegmic ovules develop into testal seeds. The testa is not similar to those seen in typical legume integuments, frequently observed in species with indehiscent fruits. However, the hilum is typical of Faboideae. Seeds are exalbuminous and embryos present cotyledons and embryonic axis well developed. From 100 fruits analyzed mophologically, 61% were one-seeded, 34% two-seeded and only 5% three-seeded. From 144 seeds evaluated, only 2% were polyembryonic, showing two embryos per unit.
Tipuana tipu; Fabaceae; fruit; seed; development
