The Orchidaceae /ɔːrkɪˈdeɪʃiː/ are a diverse and widespread family of flowering plants, with blooms that are often colourful and fragrant, commonly known as the orchid family. Along with the Asteraceae, they are one of the two largest families of flowering plants. The Orchidaceae have about 28,000 currently accepted species, distributed in about 763 genera. Orchids are easily distinguished from other plants, as they share some very evident, shared derived characteristics, or synapomorphies. Among these are: bilateral symmetry of the flower (zygomorphism), many resupinate flowers, a nearly always highly modified petal (labellum), fused stamens and carpels, and extremely small seeds. All orchids are perennial herbs that lack any permanent woody structure.