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Floral Construction and Pollination Biology in the Lamiaceae
E-mail classenb@uni-mainz.de
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Flowers are functional units for sexual reproduction. They balance several conflicting demands. These include offering pollen as a floral attractant vs. saving pollen for reproduction; availability of resources vs. the need for elaborate displays to attract pollinators; and ensuring the production of offspring by self-pollination vs. the need to increase genetic diversity by outcrossing. Each flower can thus be regarded as a species-specific compromise for managing sexual reproduction. Its ‘floral construction’ is defined as the syndrome of adaptive characters needed for pollen transfer that have evolved under phylogenetic, developmental and environmental constraints. The ‘bilabiate blossom’ characterizing the Lamiaceae is a construction for nototribic (dorsal) pollen deposition. It has evolved many times in parallel and illustrates that distantly related plants can approximate to similar functional solutions and that closely related plants can realise these solutions by diverse morphological means.
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