Included here is the southeastern part of the Arabian Peninsula including Oman and the eastermost parts of the United Arab Emirates.

Omanian Southern Limestone Escarpment and Plateau Vegetation

On the south facing, limestone slopes of Dhofar, which receive monsoon mist and clouds, deciduous woodlands occur mainly characterized by the endemic Anogeissus dhofarica (Combretaceae). Other common or co-dominant trees include Commiphora abyssinica var. simplicifolia and Delonix elata. The associated shrubs include Allophylus rubifolius, Premna resinosa, Trema orientalis and the endemic or near endemic Blepharispermum hirtum (Asteraceae), Croton confertus (Euphorbiaceae) and Maytenus dhofarensis (Celastraceae). The former is a curious plant with florets disposed in dense spherical heads. Also found here are several suffrutices including the two endemic or near endemic species Barleria aucherana (Acanthaceae) and Hybanthus durus (Violaceae). Smaller ground layer species include Meineckia phyllanthoides, Polygala rotundifolius, Desmodium ospriostreblum, Physalis micrantha, Justicia heterocarpa and the endemic or near endemic twiner Ceropegia boerhaviifolia (Asclepiadaceae). On the lower slopes the Arabian endemic Boscia arabica (Capparaceae) becomes the more prominent species often festooned with the widespread succulent vine Cissus quadrangularis. Other woody associates include the endemic Jatropha dhofarica (Euphorbiaceae), and of special interest in these woodlands in the presence of species of the endemic genera Cibirhiza (Cibirhiza dhofarensis) and Dhofarica. The ground cover consists of a thick layer of herbaceous shrubs, climbers and ferns. At altitudes exceeding about 500 m these deciduous woodlands gradually give way to semi-evergreen thickets dominated by Carrisa edulis, Dodonaea angustifolia, Euclea schimperi, Euphorbia balsamifera and Olea europaea. Moving even higher, on to the summits, grasslands with Apluda mutica and species of Cenchrus and Themeda replace the thickets. Among the associated herbs are Impatiens balsamifera and the endemic Dyschoriste dalyi (Acanthaceae). Further inland where the influence of monsoon mists decline xerophytic trees, shrubs and succulent herbs predominate. These include Acacia ethaica, Dracaena serrulata and the endemic Cocculus balfourii (Menispermaceae) and Dhofarica macleishii (family?).

Omanian Xeromorphic Open Limestone Scrub

Dry, open scrub largely dominated by Commiphora myrrha and Euphorbia larica occur on karstic coastal terraces. Other common species are Acacia ethbaica, Grewia tenax var. erthraea and Ochradenus arabicus, all of which are characteristic of this rugged karstic relief with rapid water run-off and pronounced erosion. However, species composition varies. On the mountain range south of Madinat Qabus, which is mainly karstic limestone and dolomites, the dominant taxa are jointed by various endemic or near endemic species. These include shrubs such as Ochradenus aucheri (Resedaceae) and Rhus aucheri (Anacardiaceae), chamaephytes such as Jaubertia aucheri (Rubiaceae) and Teucrium stocksianum (Lamiaceae), hemicrytophytes such as Caralluma aucheriana (Apocynaceae), Convolvulus virgatus (Convolvulaceae) and Diplotaxis harra (Brassicaceae), and therophytes like Herniaria mascatensis (Caryophyllaceae).

References

Fisher, M., Ghazanfar, S. A. & Spalton, A. 1999. The Natural History of Oman. Backhuys Publishers, Leiden.

Ghazanfar, S. A. & Fisher, M. 1998. Vegetation of the Arabian Peninsula. Kluwer Academic Publishers.

Ghazanfar, S. A. 2006. Saline and alkaline vegetation of NE Africa and the Arabian Peninsula: an overview. In: Biosaline Agriculture and Salinity Tolerance in Plants. Eds. M. Öztürk, Y. Waisel, M. A. Khan and G. Görk. Birkhäuser Verlag, Switzerland.

Miller, A. G. & Nyberg, J. A. 1991. Patterns of endemism in Arabia. Flora et Vegetatio Mundi, 9: 263-279.

Radcliffe-Smith, A. 1980. The vegetation of Dhofar. Journal of Oman Studies, Special Report No. 2: 59-86.

Zohary, M., Heyn, C. C. & Heller, D. 1980. Conspectus Florae Orientalis. The Israel Academy of Science and Humanities. Jerusalem.