Included here is the island of Socotra in the Arabian Sea just north of Somalia. The climate is monsoonal but much less arid than the adjacent mainland.

Socotran Dendrosicyos Montane Woodland

On the lower slopes of the limestone plateau, endemic plants including Dendrosicyos socotrana (Cucurbitatceae), Adenium sokotranum (Apocynaceae), Cissus subaphylla (Vitaceae) and Euphorbia arbuscula (Euphorbiaceae) combine to form a landscape unique to Socotra.  Dendrosicyos socotrana, commonly known as the cucumber tree, is the only known member of the cucumber family (Cucurbitaceae) that has evolved into a tree. Associated endemic shrubs include Maerua socotrana (Capparidaceae), Withania riebeckii (Solanaceae) and Cynanchum linifolum (Asclepiadaeae), while low growing species include endemic herbs such as Corchorus erodioides (Tiliaceae), Oldenlandia pulvinata (Asclepiadaceae), Trichodesma microcalyx (Boraginaceae), Lactuca rhynchcarpa, Pulicaria stephanocarpa and P. diversifolia (Asteraceae), and the endemic fern Adiantum balfourii (Adiantaceae).

Socotran Dorstenia-Kleinia-Ficus Woodland

At heights above 500 m the characteristic limestone endemics include Dorstenia gigas and Ficus socotrana (Moraceae) and Kleinia scottii (Asteraceae).  Other common endemics include Tatragonia pentandra (Aizoaceae), Euphorbia oblanceolata (Euphorbiaceae) and Hibiscus scottii (Malvaceae). The rock ledges support endemics such as Pseudomussaenda capsulifera (Rubiaceae), Haya obovata, Polycarpaea divaricata (Caryophyllaceae), while pockets of dark rich soil include the endemic Begonia socotrana (Begoniaceae), Exacum affine (Gentianaceae) and Pseuedanum caudatum (Apiaceae).

Socotran Dracaena-Boswellia Montane Woodland

The strange mushroom shapes of the endemic dragon tree, Dracaena cinnabari (Liliaceae) makes this one of the most distinctive communities in the world. The tree is also the source of the mysterious dragon’s blood, a type of resin that oozes from between the branches. The substance, originally thought to be made from dragons, turns red on cooking, and is in much demand throughout Arabia for its magical and curative properties. Other common endemics include Boswellia ameero, B. elongata, B. socotrana (Burseraceae), and Mitolepis intricata (Asclepiadaceae). The well-known aromatic resin frankincense, which is burned as incence, is derived from Boswellia socotrana.  This community is characteristic of the limestone slopes of the Hamadera Hills.

References

Gwynne, M. D. 1968. Socotra. In: Conservation of Vegetation in Africa south of the Sahara. Eds. I. Hedberg and O. Hedberg. Acta Phytogeogrraphica Suecica, 54: 275-279.

Miller, A. G. & Morris, M. 2004. Ethnoflora of the Soqotra Archipelago. The Royal Botanical Gardens, Edinburgh.

Milner, J. E. 1992. The Tree Book. Academic Press.

Popov, G. B. 1957. The vegetation of Socotra. Journal of the Linnean Society Botany, 55: 706-720.

White, F. 1983. The Vegetation of Africa. UNESCO.