Stigma: The portion of the pistil (female reproductive part of a flower) which is receptive to pollen.*
Looking at the bloom on the right side of the image, the stigma is visible at the tip of the pistil protruding above the anthers. The flower is Crocosmia ‘Lucifer’ blooming in the Entry Garden Walk.
*Harris, J.G., Harris, M.W. (2001). Plant identification terminology: An illustrated glossary (2nd ed.). Spring Lake: Spring Lake Publishing.