Main Article Content
Aims: To study Floristic diversity, life-form, chorology, edaphic factors affecting the species distribution of Wadi Qusai.
Study Design: Several field trips were carried out to the study area – sites soil analysis.
Place and Duration of Study: Wadi Qusai - Jazan - Saudi Arabia.
Methodology: Floristic composition, vegetation diversity, life form, chorology, soil analysis and cover estimation by TWINSPAN, DCA and CCA.
Results: A total of 103 species belonging to 77 genera and 33 families were recorded from 20 sample sites. Poaceae, Euphorbiaceae and Amaranthaceae are the most highly represented families. Therophytes and phanerophytes are the dominant life forms. Chronological analysis revealed that biregional elements that belong to the Saharo-Arabian and the Sudano-Zambezian together have the highest share of species representing 36 species (35% of the total species).
Conclusion: Five vegetation groups were recognized by TWINSPAN, DCA and CCA analysis; group A (Aloe fleurentiniorum, Cadaba glandulosa and Delonix elata) inhabiting the high wadi slope, group B (Anisotes trisulcus, Fagonia indica, Pulicaria undulata, Acacia ehrenbergiana and Panicum turgidum) was occupied the low slope and wadi terraces, group C (Ziziphus spina-christi, Abutilon pannosum and Fagonia indica) was represented the medium wadi slope, Group D (Leptadenia arborea, Salvadora persica, Dobera glabra and Jatropha pelargoniifolia) was performed the dry wadi bed and group E (Cyperus articulates, Desmostachya bipinnata, Saccharum spontaneum, Typha domingensis and) was recorded in the wet wadi bed. Groups A, B and C were positively correlated with axis 2 whereas Groups D and E were positively correlated with axis 1.Rhazya stricta has been recorded for the first time in the wadi.