Plectranthus hijazensis Abdel Khalik (Lamiaceae) is described as a new species from Al-Baha Province in Saudi Arabia. Information given on the new species includes a taxonomic description and its affinity to Plectranthus asirensis L. | Turkish Journal of Botany Research Article Turk J Bot (2016) 40: 506-513 © TÜBİTAK doi: A new species of Plectranthus (Lamiaceae) from Saudi Arabia 1,2, Kadry ABDEL KHALIK * Department of Biology, Faculty of Applied Science, Umm Al-Qura University, Makkah, Saudi Arabia 2 Department of Botany, Faculty of Science, Sohag University, Sohag, Egypt 1 Received: Accepted/Published Online: Final Version: Abstract: Plectranthus hijazensis Abdel Khalik (Lamiaceae) is described as a new species from Al-Baha Province in Saudi Arabia. Information given on the new species includes a taxonomic description and its affinity to Plectranthus asirensis L. A key to Plectranthus species of Saudi Arabia is provided, and the relationships of the species and the relevant morphological characters, particularly seed, pollen grains, trichomes, and anatomy of stem and leaf, are discussed. A distribution map of the new species and related species is provided. Key words: Plectranthus, Lamiaceae, new species, pollen, seed, anatomy 1. Introduction Lamiaceae is a large family that spread widely and adapted to nearly all habitats and altitudes. The genus Plectranthus L. is one of the largest genera of Lamiaceae and belongs to the subfamily Nepetoideae, tribe Ocimeae, and subtribe Plectranthinae. Plectranthus comprises about 300 species distributed in both tropical and warm regions of the Old World (Codd, 1985; Retief, 2000). Some species of Plectranthus are difficult to identify because of a lack of clear-cut morphological criteria to discriminate not only among species within the genus but also among the closely related genera. This has resulted in numerous taxonomic problems in the naming of species with the result that species have often been placed in several closely related genera like Coleus Lour. (Paton et al., 2004). In the Flora of Saudi Arabia, Collenette (1999) described Plectranthus with
