Classification was a key practice of the natural history sciences in the early 19th century, but leading taxonomists disagreed over basic matters, such as how many species the British flora contained. In this arena, the impact of Charles Darwin’s ideas was surprisingly limited. For taxonomists like Darwin’s friend, Joseph Dalton Hooker, the priority was to establish a reputation as a philosophical naturalist, and to do so Hooker embarked on a survey of global vegetation patterns. He believed that taxonomic “splitters” hindered his ambition to create natural laws for botany (and hence establish it as a prestigious science) by generating a multitude of redundant synonyms for every plant variety. Despite the fact that Darwin’s ideas apparently promised a justification for splitting, they also offered a philosophical justification for Hooker’s taxonomic practice, and so he enthusiastically championed his friend.