Anatomía de especies mexicanas de los géneros Phoradendron y Psittacanthus, endémicos del Nuevo Mundo

Abstract

Phoradendron and Psittacanthus only grow in America and they include hemiparasitic plants. The anatomy of Mexican species is partial and some of them had not anatomically been studied. The vegetative and reproductive anatomy of 5 species was described as seen in slides obtained through microtome, by free hand, and macerated and clarified tissues. Histochemistry tests on fresh material were made. The leaves have paracytic stomata, reticulate actinodromous venation, lateral veins with terminal portions modified to dilated tracheids and isobilateral or homogenous mesophyll. Druses are abundant in petiole and lamina of Phoradendron. The stem has xylcm vessels in radial raws and druses and brachysclereids are common in the cortical parenchyma and the pith. Pollen is spherical or triangular and tricolporate. In Psittacanthus, under ovary a tissue of cells with lignified and thickness walls is present. The viscid tissue of the fruit of Psittacanthus is bigger. Prismatic crystals, striated cuticle, suberous peridermis and vascular bundles in the exocarp had not previously been described in these species. Astrosclereids with prismatic crystals, a heterogeneous cortex, a cuticular epithelium and a striated cuticle described for other authors were not found. Pectic substances and phenolic compounds are most abundant in Psittacanthus.