The most popular varieties of tea — including black tea, green tea, Oolong tea, white tea, and chai — all come from the leaves of the evergreen shrub Camellia sinensis, otherwise known as the tea tree. Despite tea’s cultural and economic significance, relatively little is known about the shrub behind the tea leaves. However, the first draft of the tea tree genome may help explain why tea leaves are so rich in antioxidants and caffeine.