Cimicifuga simplex has three genetically and ecologically distinct pollination morphs with different flowering phenology, flower sex expressions, and selfing rates. A previous study showed that strong protandry in hermaphroditic flowers of C. simplex causes there to be seasonal minority sexes; for example, unisexual female ramets are advantageous in the first half of the flowering season and bloom then (minority sex hypothesis). That study, however, did not distinguish among the three pollination morphs of C. simplex. We investigated seasonal sex ratio changes and pollinator environments of the three morphs to verify and expand the minority sex hypothesis. We investigated flowering phenology, pollinator quantity and quality, seasonal population sex ratio dynamics, and stamen/ovule ratios in hermaphroditic flowers. We also examined the seasonal female reproductive success of hermaphroditic flowers, and the effect of male flower excision on fruit set by morph II hermaphroditic flowers. Morph I (mainly hermaphroditic and female ramets) had high pollinator quality and quantity. Fruit set of hermaphroditic ramets was high throughout the flowering season. Morph II (hermaphroditic and andromonoecious ramets) had low pollinator quality, and few pollinators visited near the beginning and end of the season. Removal of male flowers led to a pollen limitation. Morph III (hermaphroditic ramets and a high selfing rate) had very low pollinator abundance throughout the flowering season, and male and female phases largely overlapped. The scarcity of male flowers in morph I is likely a result of the high pollinator quantity and quality. The high fruit set suggests that no pollen limitation existed. The low pollinator quality and quantity of the morph II population caused it to suffer from pollen limitation and may explain the absence of unisexual female ramets in this morph. The high selfing rate of morph III may be due to the extremely low pollinator abundance. Theoretical studies have indicated that the optimal investment allocation to male and female functions depends on whether a pollen limitation exists. In C. simplex, the observed relationships between pollinator environment and reproductive systems are consistent with these theoretical models.

中文翻译：

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三种原生态植物生殖型花性别比和授粉媒介动态的季节变化

Cimicifuga simplex具有三种遗传和生态上不同的授粉形态，它们具有不同的开花物候，花性表达和自交率。先前的研究表明，在单纯形衣藻的雌雄同体花中强烈的protandry导致存在季节性的少数性别。例如，单性雌性分株在开花期的前半部有利，然后开花（少数性假设）。但是，该研究并未区分C. simplex的三种授粉形态。。我们调查了三种变体的季节性性别比变化和传粉媒介环境，以验证和扩展少数民族性别假说。我们调查了雌雄同体花的开花物候，传粉媒介数量和质量，季节性种群性别比动态以及雄蕊/胚珠比率。我们还检查了雌雄同体花的季节性雌性繁殖成功，以及雄花切除对变体II雌雄同体花结实的果实的影响。变体一（主要是雌雄同株）具有较高的授粉质量和数量。整个开花季节，雌雄同体分株的果实高。Morph II（雌雄同体和雌雄同株的分株）的传粉媒介质量低下，在季节开始和结束时很少有传粉者来访。去除雄花导致花粉受限。变种III（雌雄同体的分株和高自交率）在整个开花季节的授粉虫丰度都非常低，雄性和雌性阶段大部分重叠。授粉子数量和质量较高，可能导致变体I的雄花稀少。较高的坐果表明没有花粉限制。形态II种群的低传粉媒介质量和数量导致其受花粉限制，这可能解释了该形态中不存在单性雌性分株的原因。形态III的高自交率可能是由于极低的授粉媒介丰度所致。理论研究表明，对男性和女性功能的最佳投资分配取决于是否存在花粉限制。在 授粉子数量和质量较高，可能导致变体I的雄花稀少。较高的坐果表明没有花粉限制。形态II种群的低传粉者质量和数量导致其遭受花粉限制，这可能解释了这种形态中不存在单性雌性分株的原因。形态III的高自交率可能是由于极低的授粉媒介丰度所致。理论研究表明，对男性和女性功能的最佳投资分配取决于是否存在花粉限制。在 授粉子数量和质量较高，可能导致变体I的雄花稀少。较高的坐果表明没有花粉限制。形态II种群的低传粉者质量和数量导致其遭受花粉限制，这可能解释了这种形态中不存在单性雌性分株的原因。形态III的高自交率可能是由于极低的授粉媒介丰度所致。理论研究表明，对男性和女性功能的最佳投资分配取决于是否存在花粉限制。在 形态II种群的低传粉者质量和数量导致其遭受花粉限制，这可能解释了这种形态中不存在单性雌性分株的原因。形态III的高自交率可能是由于极低的授粉媒介丰度所致。理论研究表明，对男性和女性功能的最佳投资分配取决于是否存在花粉限制。在 形态II种群的低传粉者质量和数量导致其遭受花粉限制，这可能解释了这种形态中不存在单性雌性分株的原因。形态III的高自交率可能是由于极低的授粉媒介丰度所致。理论研究表明，对男性和女性功能的最佳投资分配取决于是否存在花粉限制。在C. simplex，观察到的授粉媒介环境与生殖系统之间的关系与这些理论模型一致。