Manual of the Trees of North America (Exclusive of Mexico)
Charles Sprague Sargent
From Wikipedia: “Charles Sprague Sargent (1841–1927) was an American botanist. He was appointed in 1872 as the first director of Harvard University’s Arnold Arboretum in Boston, Massachusetts, and held the post until his death. He published several works of botany....”
It has been said that Sargent knew more about trees than anyone else living at that time.
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