Elementos traqueais de cinco táxons de Cactaceae da caatinga pernambucana, Brasil

ABSTRACT – (Traqueary elements of five taxons of Cactaceae of the caatinga from Pernambuco State, Brazil). This work brings amorphological characterization of traqueary elements (vessels and tracheids) in root and cladode of five taxons of Cactaceae ( Harrisiaadscendens (Gurke) Britton & Rose, Melocactus × horridus Wedermann Notizbl., M . zehntneri (Britton & Rose) Luetzelb., Tacingainamoena (Schumann) N.P. Taylor & Stuppy and T . palmadora (Britton & Rose) N.P. Taylor & Stuppy) occurent in the caatinga ofPernambuco State, Brazil. The vessels elements observed in the roots and cladodes seem almost same among the studied taxons, we reobserved alternate, opposite and scalariform pitting, and simple perforation plate transversal or oblique. The tracheids (WBT) wereexclusively noted in the cladodes of four studied taxons, except Harrisia adscendens . The WBTs with annular and helical thickening arepresent in all taxons and the mix thickening is present only in Melocactus