This work brings a morphological characterization of traqueary elements (vessels and tracheids) in root and cladode of five taxons of Cactaceae (Harrisia adscendens (Gurke) Britton & Rose, Melocactus × horridus Wedermann Notizbl., M. zehntneri (Britton & Rose) Luetzelb., Tacinga inamoena (Schumann) N.P. Taylor & Stuppy and T. palmadora (Britton & Rose) N.P. Taylor & Stuppy) occurent in the caatinga of Pernambuco State, Brazil. The vessels elements observed in the roots and cladodes seem almost same among the studied taxons, were observed alternate, opposite and scalariform pitting, and simple perforation plate transversal or oblique. The tracheids (WBT) were exclusively noted in the cladodes of four studied taxons, except Harrisia adscendens. The WBTs with annular and helical thickening are present in all taxons and the mix thickening is present only in Melocactus. The vessel elements and tracheids were measured and showing that the vessel elements are longer in roots and cladodes of Melocactus and the longest WBTs were only observed in cladode of Melocactus.
anatomy; Cactaceae; caatinga; traqueary elements
