Joseph Decaisne was a French botanist and agronomist. He became an aide-naturaliste to Adrien-Henri de Jussieu (1797-1853), who served as the chair of rural botany. It was during this time that he began to study plants brought back by various travelers like those of Victor Jacquemont (1801-1832) from Asia. Decaisne used applied research, most notably on the agronomy of the madder, the yam and the ramie. He was also interested in algae.

Asa Gray is considered the most important American botanist of the 19th century. His Darwiniana was considered an important explanation of how religion and science were not necessarily mutually exclusive. Gray was adamant that a genetic connection must exist between all members of a species. He was also strongly opposed to the ideas of hybridization within one generation and special creation in the sense of its not allowing for evolution. He was a strong supporter of Darwin, although Gray's theistic evolution was guided by a Creator.