Collinson's life is a microcosm of 18th-cent. natural history. A gardener and naturalist by avocation, he was what we would now call a facilitator in natural science, disseminating botanical and horticultural knowledge during the Enlightenment. He influenced the Comte de Buffon and Linnaeus. He found clients for the Phila. naturalist John Bartram. American plants populated great estates like those of the Dukes of Richmond, Norfolk, and Bedford, as...