Floral colours and the physiology of vision

Summary

Monochromatic light is composed of energy-quanta which are all equal. Our perception of colour is thereby brought into the closest relationship with the notions of the quantum theory. Polychromatic light, however, stands on a different footing and the problem of the colour which it exhibits demands separate consideration. The relationship between the spectral composition of such light and its observed hues can only be ascertained only by the observational study of a great number of cases. It is pointed out that a vast mass of material exhibiting colour and highly suitable for investigations of this nature presents itself to us in the products of the biological activity of trees and plants,viz., their leaves, flowers and fruits.