The bi-lobed stigma (the white inner part of the flower in my photo) of Mimulus aurantiacus closes when stimulated by an animal pollinator (the pollinator for Mimulus aurantiacus is the hummingbird). In the photo, you can see that it is mostly closed. If no pollen was delivered to the stigma, it will reopen with a couple of hours. If pollen was delivered, most stigma will remain closed for the remaining lifetime of the flower.
The flower has been renamed, from Mimulus to Diplacus, but I can’t get Mimulus out of my head because it starts with M, just like the common name Monkeyflower. Jepson eFlora still considers Diplacus a synonym for Mimulus.