The aim of this paper is to present the structure of exocrine glands in P. glabrum, P. amphybium, P. minus, P. persicaria and P. punctatum, of them from section Persicaria, family Polygonaceae. The observations were performed with light, scanning and transmission electron microscope, using routine techniques for sample preparation. The structures observed at superficial view are composed of four cells flanking a small pore in the middle, and surrounded by a number of rather small cells, followed by normal epidermic cells. In the cross section the structure is composed of a great cavity filled with secretion, and communicated with the external side of the pore. The cavity is internally surrounded by a flat cell epithelium separated from the mesophyll by a layer of parenchymatic cells.