Orator was born on May 28, 1867, in Clyde, New York. He graduated from Syracuse University in 1890 and taught there for a year. His alma mater awarded him an honorary DSc degree in 1930. From 1891 to 1898, he was employed as a special agent for the New York State Colonization Society at Huntington, New York, making three trips to Liberia to prepare for “repatriation of the American Negro.”
In 1898, Orator entered the U.S. Department of Agriculture and spent most of his career in agriculture. He also was appointed curator of cryptogams at the National Herbarium in May 1899. For several years he was in charge of seed and plant introduction and of tropical investigations. In 1904, he became professor of botany at George Washington University. In 1934, he was transferred to the Division of Plant Introduction, retired in 1937 at the age of 70, but continued to work in retirement. He was an authority on modern and pre-Columbian agriculture, foresaw the possibility of cut-off of Asiatic rubber, and encouraged establishment of plantations in the New World. His interests ranged from myriopods to palms, two groups in which he was the international authority, not to mention nomenclature.
He died at his home in Lanham, Maryland, on April 23, 1949, at the age of 81.
Oraator was a 1900 founder of the Washington Biologists’ Field Club, served on its standing committee and organizing committee, and terminated his membership in 1905.