This study presents a floristic survey of orchid species occurring in the Serra do Japi in Sao Paulo, southeastern Brazil. The region studied is strategically placed in the transitional zone between interior semi-deciduous mesophytic forests and the Atlantic forest, presenting species from both formations and is characterized by semi-deciduous mesophytic forests, altitudinal forests and rocky outcrops. In the Serra do Japi the orchid family is represented by 125 species distributed among 61 genera. The most representative genus is Epidendrum, followed by Oncidium and Habenaria. Most of the...