The stems of Euphorbia pentagona (Table 1; not illustrated) are quite different, because they have uniseriate rays predominantly and store water in living fibers and axial parenchyma, not unlike other cactiform
species of Euphorbia (Carlquist, 1970).
The hoodia is a stem succulent, described as "cactiform
" because of its remarkable similarity to the unrelated cactus family.
spicigera]), which form thickets where the subsoil water is accessible, several cactiform euphorbias (Euphorbia schimperi, E.
39 The deserts of Baja California (Mexico) are dominated by cacti and other cactiform plants.
There are also many convergences in apperance between some cacti in the Americas and the cactiform euphorbias in Africa.
The Namib Desert's succulent plants include: pachycaul trees that accumulate water in their trunks, among them the Moringa ovalifolia (Moringaceae) and Commiphora saxicola (Burseraceae); the arborescent crassulacean Cotyledon paniculata; the cactiform euphorbias Euphorbia virosa, E.
The small helmeted gecko (Geckonia chazaliae) of the Atlantic Sahara shelters under cactiform species of Euphorbia.