δ¹³C values of some succulent plants from Madagascar

δ¹³C values were determined in 20 succulents from Madagascar. The values were indicative of Crassulacean Acid Metabolism in 10 species of the Didiereaceae, 4 species of the Euphorbiaceae, 2 species of the Crassulaceae and 1 species of the Cucurbitaceae. The Didiereaceae and Euphorbiaceae studied are major components of a high biomass xerophytic flora in the semi-arid southwest and south of Madagascar. Three species of the Euphorbiaceae with succulent stems and non-succulent leaves, which were cultivated outdoors in the Tananarive Botanic Garden, showed C₃ like δ¹³C values for both leaves and stems. δ¹³C values of leaf and stem material from a similar species, collected in the south of Madagascar, indicated Crassulacean Acid Metabolism.