Though it would be hard to consider him a botanist in the strict sense of the term, Charles Darwin used plants in at least three interrelated ways: in his thinking about evolution, in his own researches, and in his professional life as a whole. By the end of his long and productive career, he had completed no fewer than six books, published between 1862 and 1880, exclusively devoted to botanical subjects, in addition to botanical articles published in the weekly Gardner’s Chronicle and journals like the Agricultural Gazette (Ornduff 1984; Browne 2003; Ayres 2008; Kohn 2008). Even his magnum opus, On the Origin of Species, which drew on examples from as many types of living organisms as Darwin could find, relied heavily on plant examples to ground his famous argument (Smocovitis 2009). In their habits, mating systems, morphological structures, adaptations, distribution patterns, and even behavior, plants provided some of the best evidence in support of his theory of descent with modification by means of natural selection. After 1860, in fact, Darwin turned increasingly to botanical subjects of research.

Darwin’s Botanical Work

Darwin’s botanical works were voluminous and impressive, to be sure, but his contributions remained underappreciated or incompletely understood, until the second half of the twentieth century. This was due to several reasons. For one thing, Darwin was taxonomically promiscuous, flitting from organism to organism as his curiosity dictated or in search of appropriate examples in support of a generalizable theory of evolution. He lacked the kind of single-minded devotion to plants (or, indeed, to any one organismic system, let alone to a taxonomic group) that characterized contemporaries like Asa Gray and Joseph Hooker, both of whom were renowned in their day as systematic botanists. Darwin’s methodology, furthermore, lacked the kind of experimental rigor that was increasingly associated with late nineteenth-century botanical sciences generally and the German export of the “new” botany in particular, which stressed laboratory practice and relied heavily on microscopy and other instrumentation.