The present study characterized the root of some orchids occurring in an altitudinal field at the Parque Estadual da Serra do Brigadeiro, pointing out both ecological and taxonomical relevant characters. Only terrestrial individuals were studied, except for P. teres, a rupestrine species. Anatomical comparative analysis of the studied species reveled clear definitions of two groups: Epidendrum secundum, E. xanthinum, Oncidium barbaceniae, O. blancheti, Pleurothallis prolifera, P. teres, Zygopetalum mackayi, and Z. brachypetalum are perennial species and xerophytes, while Cleistes gracilis, Habenaria hydrophila, H. janeirensis, H. macronectar and Prescottia montana are species that present shoot reduction in order to complete life cycle before dry periods, being considered mesophyte plants. There where great similarities between genera, especially within Epidendrum, Oncidium and Pleurothallis. In the case of Habenaria, greater similarities were found between H. hydrophila and H. macronectar, due to the differences in vascular cylinder and cortex of H. janeirensis.
adaptative strategies; rocky field; taxonomy
