Fig. 5. Scanning electron microscopy and histology of developing female reproductive organs. (A) Wild-type ear showing developing spikelet pairs. (B) Double mutant ear with normal spikelet-pair initiation. (C) Wild-type spikelet pair showing two upper florets with glume (gl), palea (p), stamen primordia (arrow; st) and a gynoecial ridge (gr) that surrounds the ovule. The lower floret (lf) is visible. (D) Double mutant spikelet pair with upper floret initiating multiple floret meristems subtended by separate paleas (p). (E) Wild-type female florets showing carpels forming silk (si). (F) Double mutant florets generating abnormal organs in aberrant arrangements; ca, a carpel-like organ in the left spikelet. (G) Wild-type floret with a single, fully formed silk (si). (H) Double mutant floret with many silks. (I) Longitudinal section of a wild-type spikelet showing fully formed silk and the carpel surrounding the ovule (ov). (J) Longitudinal section of a double mutant spikelet. Ectopic florets (ef) are visible. Multiple silks arise from multiple carpel layers surrounding an ovule. (K) Double mutant spikelet showing a spiral of organ primordia at the center of one floret (*). (L) A chimeric carpel on a double mutant floret with vegetative outgrowth (v). (M) An early-arising floret replaced by an inflorescence-like structure. (N) A portion of a highly branched early floret of a double mutant plant.