However, despite having been sought since the 1930s, the exact nature of florigen is still a mystery.

Research into florigen is predominately centred around the model organism and long day plant, Arabidopsis thaliana.

Whilst much of the florigen pathways appear to be well conserved in other studied species, variations do exist.

Some of these postulated hormones, including florigen, a chemical hypothesized to induce flowering, have been sought in vain for decades.

Central to the hunt for florigen is an understanding of how plants use seasonal changes in day length to mediate flowering, a mechanism known as photoperiodism.

This led to the suggestion that florigen may be made up of two classes of flowering hormones: Gibberellins and Anthesins.

Floral initiation is the morphological transformation of an induced growing point from a vegetative to a floral primordium and involves the plant hormone florigen.

Hence the transmission of florigen, and so the induction of flowering, relies on a comparison between the plant's perception of day/night and its own internal biological clock.

However, in 2007 other group of scientists made a breakthrough saying that its not the mRNA, it is the FT Protein that is transmitted from leaves to shoot possibly acting as "Florigen".

Problems with isolating florigen and the inconsistent results acquired led to the suggestion that florigen does not exist; rather, a particular ratio of other hormones must be achieved for the plant to flower.

Florigen was first described by Russian plant physiologist Mikhail Chailakhyan, who in 1937 demonstrated that floral induction can be transmitted through a graft from an induced plant to one that has not been induced to flower.

However more recent findings indicate that florigen does exist and is produced, or at least activated, in the leaves of the plant and that this signal is then transported via the phloem to the growing tip at the shoot apical meristem where the signal acts by inducing flowering.