Fig. 4. SEM analysis of wild-type spikelet organs and fzp-2 bract-like structures. (A) Junction between the organs of a wild-type spikelet. (B) Border between the rudimentary glume and the empty glume of a wild-type spikelet. (C) The cells of empty glumes have a regular shape and a flat surface that result in a smooth overall appearance. (D) The cells of rudimentary glumes have a irregular shape and hairs that can be short or long, resulting in a rugous appearance. (E) Bract-like structure of a fzp-2 tertiary branch. An axillary meristem (arrow) is formed but its development is arrested. (F) The cells of bract-like structures of fzp mutants have irregular shape and hairs similar to the cells of wild-type rudimentary glumes. (G) Upper view of a bract-like structure and its degenerated axillary meristem (arrow) on the secondary branch of a fzp-2 spikelet. (H) Empty glume of a fzp-3 spikelet. org, outer rudimentary glume; irg, inner rudimentary glume; oeg, outer empty glume; ieg, inner empty glume; l, lemma; p, palea; eg, empty glume; rg, rudimentary glume. Scale bars: 100 µm (A,B,E,G,H); 10 µm (C,D,F).