This flower bud of the winter's bark tree, native to Central and South America, gracefully displays all the elements of the fruit process ahead of it. The orange structures, called carpels, will swell into fruit when the flower is pollinated. The longitudinally sliced carpel in the middle reveals the ovules inside, which will develop into seeds. Towards the edge of the flower bud the pollen sacs are visible, with tiny pollen grains inside.
The carpel protects the ovules, as the fruit later protects the seed. Wolfgang Stuppy writes that this gives fruiting plants tremendous evolutionary advantages over "naked seed" plants, or gymnosperms, like conifers and Ginkgos.