A study of leaf anatomy, chloroplast ultrastructure, labelling pattern after short-time 14CO2 fixation, and CO2 compensation point indicates that Chamaesyce buxifolia (Engelm. ex Hitche.) Small (Geraniales), Pectis leptocephala (Cass.) Urb. (Campanulales), and Imperata arundinacea Cyr. (Graminales) have typical features of plants exhibiting the C4-dicarboxylic acid pathway of photosynthesis. Thus it is established that the correlation of these C4 properties, well known in various orders of Monocotyledons (Graminales, Cyperales) and in the dicotyledonous order of the Centrospermae, is also characteristic of some species in other systematically widely separated orders within the Dicotyledons.