Uncaria guianensis and U. tomentosa are climbing lianas, bush lianas occuring in large areas of Brazilian Amazon and Central and South America countries. The species presented exceptional medicinal importance, with its bark, wood and leaves used by Amazon native people and pharmaceutical industries. Considering the importance of the species identification in field and laboratory conditions, the present work described the anatomical structure of Uncaria guianensis and U. tomentosa, which occurs in State of Acre, Brazil. The results showed that the wood of the species was characteristic of the Rubiaceae family, except the rounded vessel, greater and solitary, parenchyma axial diffuse and width of the rays, proper of lianas.
wood anatomy; liana; Rubiaceae; Uncaria guianensis; Uncaria tomentosa