Fig. 2. Morphology of early flowers of wild-type and mutant plants carrying ap3, pi, and sup mutations. In all flowers, the whorl one sepals or sepal primordia were removed. (A) A wild-type bud at stage 6 showing six stamen primordia (st), carpel primordia (gynoecium, g), and a tiny petal primordium (p). (B) A wild-type bud at stage 8 with clearly visible stamens and fused carpels. (C) A wild-type bud at stage 9 showing petal primordia becoming more prominent than before. (D) A stage 6 ap3-1 floral bud with sepal primordia and stamen primordia that are smaller than the normal. (E) An ap3-1 bud at about stage 10 with sepals (s), stamens (st) and filaments (f). (F) A stage 6 ap3-1 ask1-1 bud showing no stamen primordia but with sepal primordia and the central gynoecium primordium that had become flattened and enlarged at the periphery. (G) An ap3-1 ask1-1 bud at about stage 7 showing sepal, filament primordia (f) and enlarged carpel primordia. (H) An ap3-1 ask1-1 bud at about stage 10 showing sepals and filaments. (I) A late stage 6 ap3-3 bud without stamen primordia, but with sepal primordia and a gynoecium primordium that is enlarged and misshapen. (J) An ap3-3 bud at about stage 10 showing sepals and filamentous organs. (K) A stage 6 ap3-3 ask1-1 bud with sepal primordia which are fewer than in ap3-3, and the enlarged gynoecium primordium is similar to ap3-3. (L) An ap3-3 ask1-1 bud at about stage 10 with one small sepal-like (s) organ but no filaments. (M) A stage 6 ap3-3 ufo-2 ask1-1 triple mutant bud showing enlarged carpel primordia but no sepal primordia. (N) An ap3-3 ufo-2 ask1-1 bud at about stage 10 having only the gynoecium interior to the removed whorl one sepals. (O) A pi-1 bud at stage 6 showing sepal primordia and anenlarged gynoecium primordium. (P) A pi-1 bud at about stage 10 showing sepals and filaments. (Q) A stage 6 pi-1 ask1-1 bud showing enlarged carpel primordia but no sepal primordia. (R) A pi-1 ask1-1 bud at about stage 10 with filaments but without sepals. (S) A pi-1 ufo-2 ask1-1 bud at about stage 10 with one filament but no sepals. (T) A stage 6 sup-1 bud that has six stamen primordia and is beginning to form two more stamen primordia (arrows). (U) A sup-1 bud at stage 9 showing 6 large stamens and two small stamens, but no detectable carpel structure. (V) A sup-1 ask1-1 bud at late stage 6 that has six stamen primordia and is begimming to form one more stamen primordium (arrow). (W) A sup-1 ask1-1 bud at stage 8 showing six stamens and fused carpels (g). (X) A sup-1 ufo-2 ask1-1 triple mutant bud at late stage 6 showing a phenotype similar to that of the sup-1 ask 1-1 bud with filament primordia and fewer stamen primordia. The gynoecium primordium was also larger than that of the sup-1 ask1-1. Scale bars, in A (A,T,V,X) 10 µm; in D (D,F,G,I,K,M,O,Q) 10 µm; in B (B,C,H,L,N,R,S,W) 50 µm; in E (E,J,P,U) 50 µm.