Biol 324 Introduction to seed plant taxonomy
Autogamy: Self-pollination syndrome
Characteristics
- flowers small, often white, no nectar guides, nectaries, or fragrance
- corolla parts often reduced or sometimes absent (not showy)
- anthers and stigmas in close proximity, no dichogamy*
- pollen often shed before flower opens and produced in small amounts.
- absence of dichogamy = maturation of stamens and pistils occurs at different times, thus preventing self-pollination
Ecology
- Self pollinated plants are usually annuals, and many weeds are self pollinated
- Most common in areas with a pronounced dry season or unpredictable growing season, such as deserts (or weedy, disturbed habitats).
Reproductive assurance – survival to next generation is not dependent on being in close proximity to a mate
Examples
(1) Self-pollinating and outcrossing Senecio
Senecio squalidus – cross – ray flowers (around edge of inflorescence)
Senecio vulgaris – selfer, small, relatively inconspicuous inflorescences, loss of attractive corolla lobes
(2) Epilobium self and cross
Epilobium angustifolium vs E. ciliatum,
Epilobium ciliatum – self, borrring!
Epilobium angustifolium – cross, beautiful fireweed
(3) Plectritis - self and cross
Plectritis congesta vs P. brachystemon
Plectritis brachystemon – self, little white thing
Plectritis congesta – cross, pretty