In this study, the micromorphological characters of 17 species belonging to seven genera of family Malvaceae present in Saudi Arabia were examined. These characters used in analyzing the phylogenetic relationship among the studied species viz., shape of stem, petiole and leaf in cross section, trichomes, crystals, ducts, star- shape idioblasts, secondary vascular tissue system in stem and petiole vasculature. The anatomical features are used for the preparation of an identification key. Depending on the presence of trichomes, the studied species separate in two main groups; first group contain the species of Althaea, Hibiscus and Malva (their classification depend on the stem vascular system), second group contain the four remaining genera where their classification depend on many attributes such as, cross section of stem, petiole and leaf, arrangement of trichomes, ducts.
Key words: Abutilon, Althaea, Anatomy, Fioria, Hibiscus, Leaf, Malva, Malvaceae, Pavonia, Petiole, Senra, Stem.
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