Fig. 5. rgo1 spikelet development has several possible outcomes. (A,E) Wild type spikelets have one silk (si), a single ovule primordium (op) and an aborting lower floret (af) surrounded by the outer glume (og) and inner glume (ig). (B-D,F-H) rgo1 mutant spikelets have three florets. The two lower florets abort in some spikelets (B,F). In other spikelets, only the first floret aborts, resulting in two functional flowers (C,G) and a pair of opposed kernels. Rarely, the two developing florets are fused (D,H), and produce a fused kernel. Bars, 100 µm (A-D), 250 µm (E-H).