Pyrus calleryana, or the Callery pear, is a species of pear tree native to China and Vietnam, in the family Rosaceae. It is most commonly known for its cultivar 'Bradford' and its offensive odor, widely planted throughout the United States and increasingly regarded as an invasive species. Pyrus calleryana is deciduous, growing to tall, often with a conical to rounded crown. The leaves are oval, long, glossy dark green above, on long pedicels that make them flash their slightly paler undersides in a breeze. The white, five-petaled flowers are about in diameter. They are produced abundantly in early spring, before the leaves expand fully. The fruits (which are often assumed to be inedible due to their abundant, cyanide laced seeds) of the Callery pear are small (less than in diameter), and hard, almost woody, until softened by frost, after which they are readily taken by birds, which disperse the seeds in their droppings. In summer, the shining foliage is dark green and very smooth, and in autumn the leaves commonly turn brilliant colors, ranging from yellow and orange to more commonly red, pink, purple, and bronze. However, since the color often develops very late in autumn, the leaves may be killed by a hard frost before full color can develop. Callery pears are remarkably resistant to disease or fireblight. However, some cultivars, such as 'Bradford', are particularly susceptible to storm damage and are regularly disfigured or killed by strong winds, winter weather, or limb loss due to their naturally rapid growth rate. The species is named after the Italian-French Joseph-Marie Callery (1810–1862), a sinologue who sent specimens of the tree to Europe from China. Cultivation Numerous cultivars of Callery pear are offered commercially, including 'Aristocrat', 'Autumn Blaze', 'Bradford', 'Capital', 'Chanticleer' (also known as 'Cleveland Select'), 'New Bradford', 'Redspire', and 'Whitehouse'. In the United States The trees were introduced to the U.S. by the United States Department of Agriculture facility at Glenn Dale, Maryland, as ornamental landscape trees in the mid-1960s. They became popular with landscapers because they were inexpensive, transported well and grew quickly. Lady Bird Johnson promoted the tree in 1966 by planting one in downtown Washington, D.C. The New York Times also promoted the tree saying, "Few trees possess every desired attribute, but the Bradford ornamental pear comes unusually close to the ideal." In much of North America these cultivars, particularly 'Bradford', are widely planted as ornamental trees.