The anatomy and mode of growth of the heteroarthrocarpic fruits ofTrachystoma (T. apbanoneummMaire & Weiller,T. balliiO. E. Schulz andT. labasii Maire)andCeratocnemum (C. rapistroidesCoss. & Bal.) are studied; the fruit ofErucastrum littoreum(Pau & F. Quer) Maire is also included for comparison as it shows the same trend developed to a much lesser extent. A short description of all present tissues is given. Evaluations of the growth of ovaries and siliques have shown that a) mitosis continues in these fruits after anthesis, and b) the bigger a fruit segment (valvar or rostral) is, the higher mitotic activity is registered. The presence of layers of abscission tissue between the replum and the valvae is here considered to be a sign of primitiveness. In general, fruit anatomy is closely related to other exomorphological characters.