Taxonomic significances of seed morphology in some tribes of subfamily Malvoideae (Malvaceae) in Saudi Arabia

In this study, we evaluated the taxonomic significance and seed macro and micromorphological characteristics of 28 species belong to eight genera of subfamily Malvoideae (Malvaceae) from Saudi Arabia. The genotypes were studied using light and scanning electron microscope (SEM). Macro- and micromorphological characters of the seeds are presented, including shape, color, size, hairs, surface pattern, epidermal cell shape, anticlinal boundaries, and periclinal cell wall. The taxonomic and phylogenetic implications of seed coat micromorphology were compared with those of the available gross morphological and molecular data (ISSR and SCOT). Seed character analysis offered useful data for evaluating the taxonomy of Malvoideae on both intrageneric and tribal levels. Monophyly of the genera Abutilon, Malva and Pavonia was supported. Moreover, these analyses supported previous phylogenetic data, indicating that distinct lines are present within the genus Hibiscus and Sida, indicating that these genera are not monophyletic. A key is provided for identifying the investigated taxa based on seed characters