Bird of paradise or crane flower is a short shrub native to South Africa, though its flowers are commonly seen in fairly expensive cut flower arrangements around the world.
At first glance, its flowers may confuse as to how they are structured, but it isn’t too difficult to decipher. The orange-yellow parts are sepals, not petals. It does have petals, though, and they have two forms. One is the thumb-shaped nub at the base of the long dark-coloured structure in the centre of the flower–this is the free petal. The other petals are united into the structure that resembles a toothed bird’s beak. If you were to peel these united petals back along the toothed groove, you’d find the pollen-producing anthers. The stigma, or pollen-receiving surface, extends outwards beyond the united petals.
Botany / photography resource link: Kurt Stüber’s Index of Four Thousand Botanical Images, indexed by numerical order, plant name and family.