Summary
Microscopic analysis on wood samples of Bixa arborea Huber, a Bixaceae, showed the occurrence of a not exclusively parenchymatous radial structure. Such phenomenon is equivalent to only three other cases recorded In the revised literature, for Angiospermae species. This research has also evidenced the presence of axial vessel members not forming part of definite axial rows. The present work documents and describes the xylem of this species emphasizing the anomalous structures observed.