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 it 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).