Fig. 2. Scanning electron micrographs of developing mutant and transgenic flowers. The top row shows inflorescence shoot apices (meristem indicated with an asterisk) surrounded by developing flowers. Numbers indicate floral stages (Smyth et al., 1990). (A,E,I,M) Wild type. (E) Stage 5 flower, with two sepals (se) dissected away to reveal the developing stamens (st) and the floral meristem (fm), which has begun to form the central gynoecium consisting of congenitally fused carpels. (I) Stage 7 flower, in which the floral meristem has terminated with the formation of carpels (ca). (M) Mature flower with four whorls or organs, including sepals, petals (pe), stamens and carpels. (B,F,J,N) Strong LFY:VP16 line. Note supernumerary organs in the first whorl (1st) of developing flowers (F). The floral meristem is enlarged compared to that of the wild type and is beginning to produce another set of four organ primordia. (J) Three partially fused carpels are found in the center, which appear to have almost spiral phyllotaxy. A floral meristem is still visible in the center. (N) A mature flower that consists of several carpels and carpelloid organs that lack a clear whorled arrangement. (C,G,K,O) ag-1. The floral meristem persists and produces many whorls of organs that develop into sepals and petals. The floral meristem is indicated by an asterisk in (O). (D,H,L,P) LFY:VP16 ag-1. After the meristem has produced several whorls of organs, it reverts to an inflorescence meristem (indicated by an asterisk) that produces secondary flowers (sf). Note the enlarged floral meristem in H. Scale bars 50 µm (A-D, I-L), 20 µm (E-H), and 500 µm (M-P).