Colleters are secretory structures, with a protective function, that occur in different organs and in many Angiospermae families. The aim of this work was to describe the anatomy and micromorphology of colleters present in Psychotria nuda (Cham. & Schltdl.) Wawra as well as analyze the structure and composition of crystals from the central axis of the structure under study. The material was collected at the Tinguá Biological Reserve and processed according to usual techniques for light and scanning electron microscopy. The colleters are of the lachrymiform type, with an elongated central axis, formed by fundamental parenchyma, sheathed by a palisade layer, responsible for the secretion. Raphid crystals were observed in the central axis of the colleters. By X-ray microanalysis it was possible to show calcium predominance in these structures.
Calcium crystals; colleters; secretory structure; Rubiaceae
