Orchid flower (Cypripedium calceolus). The yellow bulb-shaped part of the flower gives rise to the name of yellow lady's slipper orchid. This part of the flower is a specialised petal called a lip. It attracts and can trap pollinators. This is a terrestrial orchid (one that grows in soil). It is found in temperate regions in Asia, Europe and North America. There are more than 30,000 species of orchids worldwide, many of which are grown as ornamental flowers.