Fig. 5. Double mutant analysis with class B and C genes affecting organ identity. (A) ap3-3 mutant flowers produce sepals instead of petals in the second whorl and stamens are replaced by carpeloid, filamentous organs. (B) In the roxy1-3 ap3-3 double mutant, fewer sepals of a reduced size are formed in the second whorl. They are often bent (arrow) and resemble filamentous structures. (C) ag-1 mutant flowers display a transformation of stamens into petals and a new mutant flower is initiated in the fourth whorl. (D-F) roxy1-3 ag-1 double mutant flowers produce fewer petals in the second whorl that are often reduced in size (arrowheads in E). However, third whorl petals are not affected and occasionally formation of a new flower (arrow) can be observed in the second whorl (F).