The paper describes four recessive homeotic mutations in *Arabidopsis thaliana* that disrupt flower development. These mutations, *agamous-1* (ag), *apetala2-1* (ap2), *apetala3-1* (ap3), and *pistillata-1* (pi), affect the outcome of organ development but not the location of organ primordia. The mutations result in various homeotic transformations, such as stamens becoming petals, sepals becoming leaves, and petals becoming sepals. Two of the mutations, *ap2-1* and *pi-1*, cause the loss of certain organs, while *ag-1* causes the cells that would form the gynoecium to differentiate as a flower. Temperature-sensitive experiments indicate that the wild-type *AP2* gene product acts at the time of primordium initiation, while the *AP3* product acts later. The authors propose that these genes may be involved in setting up or responding to concentric, overlapping fields within the flower primordium. The paper also discusses the interactions of these genes in double mutants and provides a detailed description of the development of wild-type and mutant flowers using scanning electron microscopy.The paper describes four recessive homeotic mutations in *Arabidopsis thaliana* that disrupt flower development. These mutations, *agamous-1* (ag), *apetala2-1* (ap2), *apetala3-1* (ap3), and *pistillata-1* (pi), affect the outcome of organ development but not the location of organ primordia. The mutations result in various homeotic transformations, such as stamens becoming petals, sepals becoming leaves, and petals becoming sepals. Two of the mutations, *ap2-1* and *pi-1*, cause the loss of certain organs, while *ag-1* causes the cells that would form the gynoecium to differentiate as a flower. Temperature-sensitive experiments indicate that the wild-type *AP2* gene product acts at the time of primordium initiation, while the *AP3* product acts later. The authors propose that these genes may be involved in setting up or responding to concentric, overlapping fields within the flower primordium. The paper also discusses the interactions of these genes in double mutants and provides a detailed description of the development of wild-type and mutant flowers using scanning electron microscopy.