A plant protein encoded by the FLOWERING LOCUS C gene that is involved in regulating the onset of flowering in response to cues such as temperature or growth stage. In certain strains of the model plant species Arabidopsis thaliana (thale cress), e.g. it acts as a transcription factor to block expression of the key proteins responsible for initiating flowering, namely FT (see florigen) and FD. Exposure to cold conditions inhibits expression of FLC, thereby relieving repression of the FT–FD pathway and enabling flowering to proceed (see vernalization).