Anatomical structure of vegetative organs of Blutaparon vermiculare (Amaranthaceae) y Funastrum glaucum (Apocynaceae), species growing in the Venezuelan coastal zones

Abstract Blutaparon vermiculare and Funastrum glaucum grow in sandy soils with low nutrients availability and low water retention capacity, also influenced by salinity, high radiation and strong winds. The aim of this study was the anatomical characterization of vegetative organs and distinguishing characters that could be linked to habitat conditions. Roots, stems and leaves were collected and they were processed following the standard methodology for mounts observable with an optical microscope. In B. vermiculare, the roots are tri or tetrarchs with bulky cortical parenchyma cells; young stems have a typical eustele and a typical secondary vascular ring, but others lateral meristems are added; the leaves of this species are epistomatics, bifacial with abaxial aquifer parenchyma and mesophyll with stellate cells around the vascular bundles. Funastrum glaucum has diarch roots; in their young stems is evident hypodermis, palisade parenchyma and the primary vascular tissue organized in a ring with a very narrow parenchimatic radio; in secondary structure, vascular cambium with unequal activity; the leaves are fleshy, anphystomatics and bifacials with papillose abaxial epidermis. B. vermiculare is distinguished by the abundance of crystals in leaves and stems, and F. glaucum by their important starchy reservation in caules. The features that ensure their survival were discussed, among they distinguish the following: developed protective tissues, presence of water reservoir, Kranz anatomy, variants in vascular cambium activity.