Orchid flowers (Aerangis coriacea). Aerangis orchids have fragrant, white flowers that have a distinctive spur (a specialised structure, usually containing nectar). The spurs, some 30 centimetres long, curve downward from the base of the flowers (lower frame). The vine-like stem from which the flowers grow, is seen in the background. Aerangis orchids are found in the rainforests of Africa and some Indian Ocean islands. There are more than 30,000 species of orchids worldwide, and many are grown for their ornamental flowers. This orchid is from Malawi.