Journal of Environmental Sciences, 2018; Vol. 47, No. 1-2 : 13-21 13 Journal of Environmental Sciences JOESE 5 ISSN 2090-9233 Journal homepage http://Joese.mans.edu.eg Original Article Epidermal Properties of Phragmanthera Austroarabica (Endemic Species to South West of Arabian Peninsula) and Its Taxonomical Significance Hassan M. Ibrahim¹, Yasser A. El-Amier 2 * and Abdul Nasser A. Al-Gifri 3,4 1 Biology Department, Faculty of Science, Sana’a University, Yemen 2 Botany Department, Faculty of Science, Mansoura University, Egypt 3 Biology Department, Faculty of Education, Aden University, Yemen 4 Biology Department, Faculty of Science, Jazan University, Kingdom of Saudi Arabia Article Info Abstract Article history : Received 16/1/2018 Received in revised form 21/2/2018 Accepted 27/2/2018 Keywords: Phragmanthera Austroarabica Epidermal Characters Trichomes Arabian Peninsula Nigerian Phragmanthera The epidermal cells are the most numerous, largest, and least specialized as well as, are structurally and functionally variable, which includes several differentiated cell types. The present study aims to investigate the epidermal features of Phragmanthera austroarabica leaves and to evaluate its taxonomical significance. Fresh samples of P. austroarabica were collected from Heziaz, Sana'a Governorate, Yemen during the period May to September 2017. The epidermal properties of P. austroarabica (endemic species to south west of Arabian Peninsula) leaves were investigated; the epidermal cells density; ornamentation surface; stomata density; ratio and type of Phragmanthera austroarabica shows a high significant in taxonomical value for the separation between the Arabian Phragmanthera (P. austroarabica) and Nigerian Phragmanthera spp. (P. capitat; P. nigritana and P. talbotiorum). 1. Introduction  Plants are considered to be anatomically simple and composed of relatively few morphologically distinct cell types (Goldberg, 1988). Cells in the plant body are organized into the ground, vascular, and dermal tissue systems (Brooker et al., 2008). The epidermis is the outermost cell layer of the primary plant body, it is the main component of the dermal tissue system of leaves, epidermal cells have fewer chloroplasts or lack them completely, except for the guard cells (Raven et al., 2005; Evert and Eichhorn, 2006). The cells of the epidermis are structurally and functionally variable, which includes several differentiated cell types: epidermal cells, guard cells, subsidiary cells, and epidermal hairs (trichomes). The epidermal cells are the most numerous, largest, and least specialized (Hülskamp et al., 1994; Becraft, 1999). Loranthaceae, one of the mistletoe families of the sandalwood order (Santalales), is a family of flowering plants. The family is worldwide in distribution and includes about 75 *Correspondence author: Tel.: 01017229120 E-mail address: yasran@mans.edu.eg genera and 1,000 species of woody plants, characterized by parasitic nature of its species (Engler, 1897; APG, 2009). The genus Phragmanthera Tiegh. (Loranthaceae) is a hemiparasitic shrub (Miller and Cope, 1999), it includes 30 species (Chaudhary, 2001), mainly distributed in Africa and Arabian Peninsula (Burrow & Willis, 2005). According to Miller and Cope (1999) Phragmanthera austroarabica is an endemic species to south west of Arabian Peninsula (Saudi Arabia and Yemen), it is intrusive on Acacia origena, Ficus vasta and Ziziphus spina-christi (Ibrahim et al., 2014). Few studies have been done on the morphological and anatomical characters of the family Loranthacee (Barlow and Wiens, 1973; Polhill and Wiens, 1998; Jrais, 2013), as well as on the morphological (Miller and Cope, 1999; Chaudhary, 2000; Waly et al., 2010; Ibrahim et al., 2014) and anatomical (Waly, 2013) features of Phragmanthera austroarabica; however, no attempts seem to have been made to study the epidermal features of P. austroarabica leaves, therefor the present study aims to investigate the epidermal features of P. austroarabica leaves and to evaluate it taxonomical significance in comparing it with epidermal features of the Nigerian Phragmanthera spp. recorded by Ibrahim and Ayodele (2013).