Flowering phenology in species of Chamaecrista (L.) Moench: temporal generation of functionally enantiostylous dimorphic individuals.
Bezerra TT, Silva AL, da Silva Aragão JL, Matias R, Almeida NM, Machado IC.
Pollinators
Wild senna plants blooming along roadsides and meadow edges are running a daily floral shell game — alternating left- and right-curving flowers to trick pollinators into carrying pollen to a different plant instead of looping back to the same one.
Some flowers have their reproductive parts curved to one side — either left or right — which helps ensure that bees picking up pollen from one flower carry it to a flower curving the opposite way on a different plant. Scientists studying wild senna relatives found that while each plant produces roughly equal numbers of left- and right-curving flowers over a season, on any given day a plant might strongly favor one side or the other. This daily flip-flopping acts like a built-in strategy to keep pollen moving between plants rather than fertilizing the same individual over and over.
Key Findings
Across four Chamaecrista species, populations maintained a near 1:1 ratio of left- and right-curving flowers over the full flowering season, but individual plants shifted their morph proportions significantly from day to day.
Three of the four species (C. diphylla, C. rotundifolia, and C. flexuosa) showed significantly more days with unbalanced morph ratios per individual, while C. ramosa showed no difference between balanced and unbalanced days.
40 individuals per species were tracked across two flowering seasons, revealing that daily dimorphism at the individual level is a consistent pattern even when population-level ratios appear stable.
chevron_right Technical Summary
Researchers found that individual plants in four Chamaecrista species (a group of wild legumes) alternate which direction their flowers curve day-to-day, even though the population as a whole maintains a roughly equal split of left- and right-curving flowers. This daily switching may help prevent self-pollination and encourage cross-pollination between plants.
Abstract Preview
Enantiostyly is a floral polymorphism that favours cross-pollination and genetic diversity. It is characterized by flowers with styles curved to the right or to the left. The factors that regulate ...
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Species Mentioned
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