When anthers dehisce in the flower buds, pollen grains come in contact with the stigma to effect pollination. Thus, cleistogamous flowers are invariably autogamous as there is no chance of cross-pollen landing on the stigma. Cleistogamous flowers produce assured seed-set even in the absence of pollinators. Selfing maintains homozygosity but typically increases (not reduces) inbreeding depression in outbreeders. Selfing may preserve a line's traits, but segregation still occurs during meiosis; cleistogamy doesn't "prevent segregation." Cleistogamy promotes reproductive assurance, not broader adaptation to changing environments.

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