The botanical magazine = Shokubutsu-gaku-zasshi

, Volume 88, Issue 1, pp 9–30

Spectral polymorphisms in angiosperm flowers determined by differential ultraviolet reflectance


  • Frederick H. Utech
    • Biology DepartmentWashington University
    • Department of BiologyToyama University
  • Shoichi Kawano
    • Biology DepartmentWashington University
    • Department of BiologyToyama University

DOI: 10.1007/BF02498877

Cite this article as:
Utech, F.H. & Kawano, S. Bot Mag Tokyo (1975) 88: 9. doi:10.1007/BF02498877


The ultraviolet reflectance pattern of flowers from 54 species representing 22 families, many native or introduced to Japan, were surveyed. Their differential ultraviolet patterns, i.e. spectral polymorphisms, were recorded by paired photographs of fresh flowers: one taken in full sunlight and the other through a visible spectrum absorbing filter. The different types of polymorphisms observed varied from total absorption by the whole flower to limited absorption by selected floral parts, such as corolla bases (nectar guides) or anthers. Some visible spectrum polymorphisms, e.g. inAnemone andHepatica, were not associated with different ultraviolet patterns. In three species ofIris, a distinct ultraviolet absorbing landing spot and nectar, tunnel guide as well as reflecting anthers are reported. The downward exerted anthers ofSolanum nigrum which shed pollen through bee wing vibration were ultraviolet absorbent.

The implications of these ultraviolet patterns for biochemical (flavonoid), taxonomic, pollination and eco-evolutionary research are discussed. Attention is drawn to the seasonal distribution of ultraviolet radiation in the northern hemisphere and its selective role on northern floras.

Copyright information

© The Botanical Society of Japan 1975