In 1955 Hartley graduated in
botany with the academic degree
Bachelor of Science at the
University of Wisconsin-Eau Claire. In 1957 he received his
Master of Science and in 1962 his
Ph.D. degree at the
University of Iowa. From 1961 to 1965 he led an expedition of the
Commonwealth Scientific and Industrial Research Organisation to
New Guinea for the study of
phytochemicals. From 1965 to 1971 he was associative curator at the
Arnold Arboretum of
Harvard University in
Cambridge, Massachusetts. In 1971, he became a senior research scientist at CSIRO Plant Industry,
Canberra, Australia. Thomas Gordon Hartley became notable for his study on the family
Rutaceae. He described several new plant taxa and genera from
Papua New Guinea,
New Caledonia,
Australia,
Peninsular Malaysia like
Maclurodendron and
Neoschmidia and wrote revisions on genera like
Zanthoxylum and
Acronychia. In 1989, he and
Benjamin Clemens Stone made a major revision of the genera
Melicope and
Pelea when they largely synonymized the genus
Pelea with the genus
Melicope. In 1969, botanist
Hermann Otto Sleumer named a genus of plants from
New Guinea,
Hartleya (from the family
Stemonuraceae) in Hartley's honour. ==Selected works==