TYPES OF NECTAR IN ANGIOSPERMS

Authors


  • (With I figure in the text)

Summary

  • 1The nectar of 889 species and some fifty varieties of Angiosperms has been analysed by paper partition chromatography.
  • 2Ten different types of nectar are distinguished (with two or three very uncommon types in addition) and are broadly classified into:
  • (a) Nectars with dominant sucrose.
  • (b) Balanced nectars with about equal amounts of sucrose, fructose and glucose.
  • (c) Nectars with dominant fructose + glucose.
  • 3Three oligosaccharides occurring in nectar are identified and a fourth is named tentatively.
  • 4Eight hundred and twenty-eight species appear to have nectar of constant composition: sixty-one species have nectar which varies distinctly. The variation does not appear to be linked with locality or date of sampling.
  • 5The distribution of nectar types is traced through the Herbaceae.
  • 6Sucrose-dominated nectars appear to be associated with long-tubed flowers having protected nectar, and fructose +glucose-dominated nectars with ‘open’flowers having unprotected nectars.
  • 7Many humble- and honey-bee, butterfly and moth flowers have nectars with sucrose more or less strongly predominating over fructose and glucose.
  • 8The climax groups of the Cruciferae, Umbelliferae, a section of the Compositae, the Euphorbiales and the herbaceous Rosaceae have a completely broken-down nectar of equal parts of fructose and glucose which is technically honey.
  • 9The preference of Apis mellifera for certain sugar mixtures and the types of nectar in some honey-bee flowers are explored.

Ancillary