SUMMARYOur information on the extent and the distribution of the vegetation types on Socotra referable to the arid zone may be summarized as follows:1.Maritime vegetationis present over small areas along the coast of Socotra. The observed communities have been described and similar, or slightly different, ones are believed to exist to a limited extent in other parts of the island which were not seen, such as near Kalansiya and at Shoab and possibly elsewhere.2.Desert vegetation. No vegetation community can truly be ascribed to this type. There are limited gravel and sand stretches on the coastal plain, where the paucity of the vegetation is due to edaphic aridity, and parts of the limestone plateau, where perennial growth is reduced by winds, but the existing vegetation can be described as a debased form of other plant communities reaching the climax under more favourable conditions.3.Subdesert shrub and grasscovers most of the island, i.e. the whole of the southern coast, most of the northern coast and the western and central parts of the limestone plateau.4.Subdesert shrub with treesis another well‐represented vegetation type, comprising the rock communities of the limestone slopes, theBoswellia‐Dracaenacommunity of Homhil and possibly other similarly sheltered parts of the limestone plateau.5.Subdesert scrubis not represented, at least in its typical composition. On the basis of the vegetation cover one might possibly regard the denserCrotonformations as belonging to this type, but this would be atypical in relation to the communities characteristic of this type.6.Subdesert bush and thicket. The mixed thickets of the lower slopes of the Hagghier and some of the sheltered valleys within the limestone region, such as the Goahal gorge can only be ascribed to this type, even though somewhat atypical.7.Xerophilous open woodlandis not represented in its typical composition.8.Vegetation of sites where water is presentincludes numerous riverine communities and the cultivations of Socotra.9.Vegetation of semi‐arid type. The vegetation of the semi‐arid zone is confined to the highlands of the Hagghier, above the height of 850 m., where only two vegetation types can be recognized, the Open grassland and the Evergree