Alfred Rehder

Rehder in the Arnold Arboretum  library in 1898, shortly after his arrival in the U.S. Alfred Rehder (4 September 1863 in Waldenburg, Saxony – 25 July 1949 in Jamaica Plain, Massachusetts) was a German-American botanical taxonomist and dendrologist who worked at the Arnold Arboretum of Harvard University. He is generally regarded as the foremost dendrologist of his generation. Provided by Wikipedia
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