 His botanical interest seems to have started when he lived in Georgia, adjacent to the botanically unexplored regions of northern Florida.Working in near isolation, in his spare time, he had a manuscript by 1859, and visited Harvard University for five months, consulting with Asa Gray and arranging for publication of his "Flora of the Southern States", which occurred in 1860.Chapman brought out a second edition in 1884, and a third edition in 1897.