Systematic study on some Urticaceae Juss. species from Egypt

Abstract

Five out of six species belonging to the three genera of Urticaceae were collected from different location in Egypt and subjected in this study. Pollen and seed external morphological characters beside stem and lamina internal characters were examined and photographed using both Light (LM) and Scanning Electron (SEM) Microscopes to assess the use of the studied characters in the separation and identification of species. The most diagnostic characters of both stem and lamina were; dissected or continuous siphonostelic structure of the vascular tissue, dorsiventral lamina, cystolith, stinging hairs, ruminate, rugose or colliculate epidermal cell surface. As well as the shape, size, aperture type and the exine ornamentation of the pollen grains, in addition to seed surface ornamentations. These characters can be of help in the discrimination of the studied species. The most obvious variable characters obtained in constructing an artificial taxonomic key for the studied species. All the 37 characters were subjected to the classical cluster analysis (UPGMA) and the principal component analysis (PCA) using PAST version 3.16 software and clearly revealed the splitting of the studied taxa into two clusters and three groups.