Resumo

AGUDELO, Carlos A. et al. LEAF AND STEM'S ANATOMY OF AN IRESINE DIFFUSA H. Y B. EX WILLD. (AMARANTHACEAE) MORPHOTYPE FROM THE GALERA'S VOLCANO (NARIÑO), COLOMBIA. Actu Biol [online]. 2007, vol.29, n.86, pp.15-23. ISSN 0304-3584.

A leaf and stem's anatomic characterization of an Iresine diffusa H. & B. ex Wild. (Amaranthaceae) morphotype is presented for the first time. It grows up on the Galeras Volcano slopes, Pasto's town, Nariño's deparment, Colombia. The samples were fixed, included and cut and the laminas were measured in optical microscope. The anatomical description originated in a five individuals' sample, in which sections were made in leaf's margin and main vein and from the transverse and longitudinal stem. The leave's section allowed the identification of cuticle, uniestratificate adaxial epidermis and simple, short, unbranched and uniseriate trichomes. The palisade parenchyma is uniestratificate, with cylinder narrow or wide cells. The lagunar parenchyma has several layers of cell, intercellular spaces, cells with druses and bundle Kranz's type. In the main vein the collenchyma is of angular type, it has 3-6 vascular bundle. In the stem, the parenchyma tissue takes form of a ring, it has cells with druses, vascular bundle from collateral opened, sclerenchyma in islands of extraxylary fibers of perivascular type and pluriestratificate xilem, with traqueas: annuled, helicated and pointed with alternate pits. Tracheids were also observed.

Palavras-chave : anatomy; Amaranthaceae; Iresine diffusa; leaf; stem.

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