ABSTRACT
Iraq is part of the Palearctic Realm, the largest of the eight terrestrial biogeographic areas or ecozones that have been defined for the Earth. Major river ecosystems of Iraq include the Tigris and Euphrates Rivers but a number of other important tributaries to these two main systems such as the Khaboor, Greater Zab, Lesser Zab, Diyala, Kharun Rivers, Gharraf, Shatt Al-Arab, Shatt Al-Hilla and others. Desert landscapes in Iraq, which comprise much of Iraq's west and southwest are extensions of the deserts of Syria and Saudi Arabia in the west and south. Additional desert landscapes lie between the Tigris and Euphrates extending from lower Babil to Nasiria, and areas east of the Tigris from Wasit southward. The flora of Iraq is composed of five phytogeographical groups: Mediterranean; Irano-Turanian; Saharo-Sindian; Eurosiberian-Boreoamerican; and bi- and pluri-regional. The Irano-Turanian region includes two sub regions, which are Irano-Anatolian and Mesopotamian sub-regions.
