Asa Gray, who lived from November 18, 1810, to January 30, 1888, is regarded as the most significant American botanist of the 1800s. His Darwiniana was seen as a seminal account of how science and faith did not always have to conflict. Gray insisted that all members of a species have to be genetically related. Additionally, he was adamantly against the concepts of special creation, which prevents evolution, and hybridization within a single generation. Despite the fact that Gray's theistic evolution was directed by a Creator, he was a fervent Darwinist. Throughout his many years as a botany professor at Harvard University, Gray maintained regular correspondence and visits with many of the top natural scientists of the day, including Charles Darwin, who thought highly of him. In addition to visits to the southern and western regions of the United States, Gray made multiple travels to Europe in order to work with prominent European scientists of the day. He also established a wide network of collectors of specimens. Being a prolific writer, he played a significant role in bringing North American plant taxonomy together.