Biogeography and diversity of the Tubiflorae in Egypt

The species distribution and biogeography of the Egyptian Tubifl orae were examined in detail. We found 284 species of vascular plants belonging to 96 genera and 12 families. The most species-rich families were Scrophulariaceae, Boraginaceae, Labitae, Convolvulaceae and Solanaceae, constituting more than 85% of total species in the order. The generic spectrum was dominated by a suite of species-rich genera (Convolvulus, Heliotropium, Veronica, Solanum, Salvia, Cuscuta, Echium, Ipomoea, Orobanche). Therophytes were the most dominant life forms among the families, followed by chamaephytes and hemicryptophytes. Boraginaceae and Scrophulariaceae had the highest share of annuals. Remarkable distribution patterns of the life forms in the seven studied biogeographic zones were noted. Trees were dominant in the Mediterranean zone, while shrubs, perennial herbs and therophytes were dominant in the Sinai. Altogether 8 endemic species and 14 near-endemics were included in the Tubifl orae of Egypt, mostly from southern Sinai. We found that Labiatae and Scrophulariaceae were the families with a higher concentration of endemics. Notably, Teucrium was among the genera of Mediterranean Africa with the highest endemism. Gamma diversity varied from 171 in the Sinai Peninsula to 43 and 39 in the oases of the Western Desert and along the Red Sea, respectively. Interestingly, the highest signifi cant values of similarity and species turnover (beta diversity) were found between the oases and the Nile lands. We note the combined effect of both temperature and precipitation on the species richness of Tubifl orae in the seven biogeographic zones. Almost half of the species showed a certain degree of consistency, that is, with narrow geographic expansion. On the basis of UPGMA clustering and PCoA analysis, 4 fl oristic groups were recognized, each including one or more biogeographic zones. The occurrence of the species of Tubifl orae in adjacent regional fl oras and their phytochorological affi nities are discussed.