Plant Systematics and Evolution

, Volume 156, Issue 3–4, pp 159–176

Self-isolation and insect pollination in the primitive angiosperms: New evaluations of older hypotheses

  • Peter Bernhardt
  • Leonard B. Thien
Article

DOI: 10.1007/BF00936071

Cite this article as:
Bernhardt, P. & Thien, L.B. Pl Syst Evol (1987) 156: 159. doi:10.1007/BF00936071

Abstract

A review of the literature, compiled over the past 40 years suggests new directions for theories discussing the evolution of reproductive isolation and entomophily in angiosperms. Data on breeding systems suggests that the protoangiosperms may have developed gametophytic self-incompatibility. Protogyny is probably ancestral to protandry and herkogamy. Although the proto-flowers were bisexual wide variation in the number of sexual organs within proto-flowers probably led to labile sexuality and early trends towards dicliny. Beetle-pollination in extant relicts appears too specialized to represent an ancestral condition. Rather, the proto-flowers may have been generalist entomophiles incorporating some beetles,Plecoptera, thrips, micropterigid moths and proto-dipterans into their fluctuating spectra of opportunistic pollinators. Bee-pollination is probably polyphyletic in origin evolving repeatedly from angiosperms showing these generalist syndromes. There is still no correlation between primitive bees (especiallyColletidae) and the relictual angiosperms. Pollen that is usually retained within the anthers following dehiscence and the presence of staminal filaments and styles characterizes most of the flowers of those relictual angiosperms pollinated by specialized, modernApoidea.

Key words

Arecales Cyclanthales Dilleniaceae Magnoliidae Angiosperm evolution bees beetles dichogamy dicliny insects protandry protogyny 

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Copyright information

© Springer-Verlag 1987

Authors and Affiliations

  • Peter Bernhardt
    • 1
  • Leonard B. Thien
    • 2
  1. 1.Department of BiologySt. Louis UniversitySt. LouisUSA
  2. 2.Department of BiologyTulane UniversityNew OrleansUSA

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