Of the many influential scientists and works of the eighteenth century, no one was more influential than Carl Linnæus (1707—1778) and perhaps no work more botanically influential than his Species plantarum (1753). Although the extent of influence is always difficult to measure and substantiate, it simply cannot be overstated in the case of Linnæus. One could, no doubt, point to the countless editions, translations, popularizations, and illustrations of his works; the societies formed because of him, and the physical gardens arranged according to his method, but one event crystallizes well enough the longevity of his thinking.

In 1867, the International Botanical Congress agreed on four laws for naming each and every plant. The third law states that if a plant has more than one recognized name, then the name that was published after May 1, 1753 shall be established as the official one. This date marks the publication of the first edition of the Species plantarum, effectively making it the beginning of modern taxonomy, since all of its 7,300 plant names immediately became the only valid ones—so much so that, complications and revisions notwithstanding, Linnæus’ names for plants are the same ones used by scientists today and will continue to be for the foreseeable future. Linnæus even continues to have a hand in the naming of plants discovered after the publication of the Species plantarum by means of his binomial nomenclature. This naming convention, which governs the identity of every organism in nature, produces the species name by combining the genus name with a single, specific epithet, as in Homo sapiens or our Canna indica. This botanical species is of concern here, because it is the very first plant listed in the Species plantarum. Therefore, if we are to enter Linnæus’ system and get some sense of how it works, C. indica will be the plant that greets us in the doorway.

We, along with botanists of the eighteenth and early nineteenth centuries, would determine the identity of this species by following Linnæus’ sexual method. Because of the simplicity and comprehensiveness that allowed for the quick identification and classification of plants at home and in the field, this method became immensely popular in its day. The sexual method was so-called because it relied on the plant’s reproductive organs, its stamen(s) and pistil(s).

Hence, to identify the C. indica requires the following process. First, we must determine the larger category of the vegetable kingdom, the class of the plant, of which there were 24. The first 23 classes were phanerogamous, that is, they had “public marriages,” in Darwin’s translation, which meant that the plant’s reproductive organs were readily observable. In contrast, the 24^th class, the cryptogams, which included ferns, mosses, algae, and fungi, had “clandestine marriages,”, since their reproductive organs were difficult or outright impossible to observe. The C. indica, however, has a readily observable stamen and pistil and thus belongs to one of the first 23 classes. But which one?

We ascertain this by counting the number of stamens: the C. indica has only one. It consequently belongs to the first class, Monandria or one male. (Counting stamens works for the first 13 classes, but things get a bit more complicated after that: it becomes necessary to observe not only number, but also proportion, union, and separation of the stamens.) Then, we must figure out the next largest category, the order, which is based on the female reproductive organs. C. indica has just one pistil, meaning that it falls into the first order, Monogynia or one female. From there, we only need to tend to the description of its genus and species to identify it precisely.

By belonging to the first class and order, C. indica is a monogamous plant. However, “The first class, Monandria, in the system of Linnæus is a very small one; comprising ... but two orders. There are also but eighteen genera in it, and forty-four species. Very few of these plants are natives of Europe; and the Indian sorts are not easy to be met with, at least in flower, in the best hot-houses.” This passage stems from Jacques-Jean Rousseau’s fantastic Letters on the Elements of Botany: Addressed to a Lady. Rousseau, who was just as well known in the eighteenth century for his botanical works as for his political ones, is drawing attention to the fact that monogamous plants are far and few between, more frequently met with in India than in Europe. These circumstances provide some context for Dr. Shaw’s jarring verse that is intended to be a celebration of a committed marriage. In this respect, Dr. Shaw describes the Indian practice of Sati, a widow's self-immolation after the death of her husband, as “A cheerful victim at that shrine/ Where nuptial truth can conquer pain.” Despite these references to India, C. indica actually originated from Central and South America (as seen on the distribution map), but the confusion perpetuated by Columbus persisted still at this time.

All of these factors demonstrate the rarity of monogamous plants, especially in Europe. This point is underscored when one realizes what it implies: every other class and order of phanerogamous plants must then be non-monogamous. Indeed, these plant marriages are variously configured in terms of bigamy, polygamy, gynandria, and so on.

The sexual politics inherent in these configurations were not lost on the eighteenth century. Although Linnæus erected this sexual system, and did not hesitate to draw analogies between plants and humans, he nevertheless cleaved to the system’s most conservative meaning, unwilling to extend these nuptial possibilities to the human world. In contrast, while Darwin certainly characterizes the monogamous C. indica as a “virtuous pair” in his verse, he did not shy away from exploiting the licentious possibilities of the sexual system as well. This is apparent in his treatment of Adonis annua, the last species to be mentioned in his poem, where monogamy has been supplanted by polygamy.