SummaryThe development of wild‐type Arabidopsis thaliana (L.) Heyhn and two late‐flowering fve mutants has been analysed under different environmental conditions. In wild‐type plants, short‐day photoperiods delay the floral transition as a consequence of lengthening all the developmental phases of the plant. Moreover, short days also alter the inflorescence structure by reducing the internode elongation and delaying the establishment of the floral developmental programme in the lateral meristems of the inflorescence and co‐florescences. Mutations at the FVE locus cause a delay in flowering time, and a change in the inflorescence structure, similar to the effect of short photoperiods on wild‐type plants. However, the effect of the fve mutations is additive to the effect of short days, and all the aspects of the Fve phenotype are corrected by vernalization. These results seem to indicate that FVE is not simply involved in timing the transition from vegetative to reproductive growth, but that it could play a role during all stages of plant development.