Reflection of Near-Ultraviolet Radiation From Flowers of Australian Native Plants

Abstract

Eighty-six species of Australian native plants were assessed in the near-ultraviolet (UV-A) (320-400 nm) and visible regions of the electromagnetic spectrum. Relationships between flower colour, size, symmetry and UV-A reflection were examined. The frequency of species in this sample that reflected UV-A radiation was found to be consistent with major overseas studies. A quantitative photographic study of the spectral reflection from the yellow flower of Hibbertia obtusifolia DC. (Dilleniaceae) was conducted for radiation with wavelengths of 280-800 nm. How an insect with UV-A-, blue- and green-sensitive photoreceptors might see H. obtusifolia as a two-coloured flower, and how this could aid a floral visitor's orientation is discussed.