The family Salicaceae in Egypt is represented by three wild species namely; Salix tetrasperma Roxb., Salix safsaf Trautv. (latter treated as Salix mucronata Thunb.), and Populus euphratica Oliv. Salix roots prefer growing in the saturated groundwater zone and will rapidly elongate to maintain contact with free water. The present study showed that S. tetrasperma was collected only from Minya to Alexandria a habitat characterized by low-temperature, absent from Upper Egypt where high-temperature. the occurrence of S. tetrasperma and both male and female S. mucronata in Fayium may be attributed...