From 1993 to 2008, he was the Palm Biologist at Fairchild Tropical Botanic Garden.
From 2008 to 2017, he served as the curator for the Florida International University Wertheim Conservatory.
[3] He has done botanical research in the Western Pacific, Caribbean, Central America, South America, Madagascar, Malesia and the continental United States[4] and published over 175 scientific and popular articles.
[5] In late 2022, his book, A Gardener's Guide to Botany, was published by Cool Springs Press, an imprint of the Quarto Group.
A palm from New Guinea, Orania zonae A.P.Keim & J.Dransf., was named in his honor in 2012.