Question

In Primula heterostyly, which pollen pollinates the pin flower stigma?

Options

• Pollen from the thrum flower's high-positioned anthers

• Any pollen regardless of source

• Pollen from flowers with matching style lengths

• Pollen from the pin flower's own low-positioned anthers

Answer 1

In Primula, the pin flower's high stigma is pollinated by pollen from the thrum flower's high anthers. When a pollinator visits both morphs, pollen from high anthers reaches the pin flower's high stigma, while pollen from low anthers reaches the thrum flower's low stigma, ensuring reciprocal pollination between morphs.