Floral specialization and pollination: a quantitative analysis and comparison of the Leppik and the Faegri and van der Pijl classification systems

Abstract

Classes of blossoms (here defined as pollination units, flowers, inflorescences, or flower‐inflorescences) of two classification systems (Leppik, 1969, and Faegri & van der Pijl, 1979) were evaluated for 1,495 samples from 1,235 plant species according to pollination unit, pollination system specialization (polyphily, oligophily, monophily, and anemophily) and pollinating agent classes. Residual analysis of blossom classes according to the Leppik system showed that: polyphilous flowers are pleomorphic and stereomorphic; polyphilous inflorescences are haplomorphic; monophilous flowers are zygomorphic; and anemophilous inflorescences are amorphic. Pleomorphic flowers are pollinated by bees, flies, and wasps; stereomorphic flowers are pollinated by bees, butterflies, moths, birds, and bats; zygomorphic flowers are pollinated by bees, and beetles; and amorphic inflorescences are wind‐ and beetle‐pollinated species. Residual analysis of blossom classes according to the Faegri & van der Pijl system showed that: polyphilous flowers are mostly dish‐, bell‐, and tube‐blossom types; monophilous flowers are flag‐, gullet‐, and trap‐blossom types; and inflorescence anemophilous are brush‐blossom type. Dish‐flowers are pollinated by bees, flies, and wasps; tube‐flowers are pollinated by butterflies, moths, and birds; flag‐ and gullet‐flowers are pollinated by bees; brush‐inflorescences are pollinated by wind; and trap‐inflorescences are pollinated by beetles. Relationships between blossom types (Leppik vs. Faegri & van der Pijl) are statistically significant: (1) amorphic and haplomorphic, are each associated with brush‐blossoms, (2) actinomorphic and pleomorphic blossoms are each associated with dish‐blossoms, (3) tube and bell‐blossoms are associated with stereomorphic blossoms, and (4) zygomorphic and paramorphic blossoms are each associated with flag‐ and gullet‐blossoms. Further, statistically significant differences were found in fruit set in relation to pollination unit, and among blossom types in both the Faegri & van der Pijl and the Leppik systems. Inflorescences produced significantly more fruit per flower than the pollination unit alone of flower or flower‐inflorescence. Gullet‐shaped blossoms exhibit the lowest fruit set; the highest fruit set is found in inconspicuous and trap‐blossoms. The lowest values for fruit set are found for zygomorphic and paramorphic blossoms, and the highest are haplomorphic and actinomorphic blossoms.