Fig. 7.

Bundle sheath development from clearings of C₃ and C₄ Flaveria leaves. (A, C, E) Bundle sheath cells are indistinct from mesophyll in developing leaves of C₃ F. robusta. Insets with arrows show enlargement of bundle sheath cells and lack of distinguishing morphological features. (B, D, F) Bundle sheath cells are distinct from mesophyll in developing leaves of C₄ F. bidentis. Insets with arrows demonstrate bundle sheath cells enlarging in perpendicular diameter in younger leaves, and in parallel diameter in older leaves. Scale bar: all images = 100 µm; insets are 2×.