Lewis and Clark may get all the press, but they based their studies of this continent’s natural history on the discoveries of their older contemporary William Bartram, and his father John, our first full-time botanist. In fictive, Thoreau-like journal entries, Ray traces the Bartrams’ many expeditions, from the Catskills to Florida, taking William from childhood to his father’s death in 1777, while highlighting his intense interest in the natural world: “Nature has been my teacher, and I have followed its paths with an open heart to learn its wonders.” Ray illustrates each passage with a mix of maps, sketches, and larger scenes of the two figures in settings from forest to swamp. She closes with one of William’s own botanical illustrations (of a small tree named for Ben Franklin, a family friend), biographical recaps for both Bartrams, and a partial list of the hundreds of native plants they collected and described. Required reading for young students of nature or American history. (bibliography) (Picture book/nonfiction. 8-10)