Linnaeus’s Botanical Clocks: Chronobiological Mechanisms in the Scientific Poetry of Erasmus Darwin, Charlotte Smith, and Felicia Hemans

MELISSA BAILES Linnaeus’s Botanical Clocks: Chronobiological Mechanisms in the Scientific Poetry of Erasmus Darwin, Charlotte Smith, and Felicia Hemans W HEN JAMES COX, THE RENOWNED INVENTOR AND JEWELER, OPENED HIS London museum in 1772, revealing to the public a series of elabo­ rately crafted mechanical clocks and automata of exotic animals, plants, and human figures, four of his twenty-three “magnificent” and “useful” pieces showcased mechanical flowers “unfolding and closing again like nature.”1 In his final and “most distinguished display,” bouquets of these unfolding flowers contained in the center-flower of each “a curious time-piece,” keeping the rhythms of the plants’ mechanical movements.2 Cox’s me­ chanical flowers, associating nature, motion, and time, dramatize one side ofcontemporary debates about whether the movements ofbiological plants more closely analogized such passive, clockwork automatons, or instead might illustrate a form of sentiency, inviting human analogy. British Romantic poetry variously represents flowers along a temporal spectrum spanning from fleeting to time-transcending possibilities, engag­ ing with these connected contentions about plants’ physiological capacities for motion and feeling.3 For example, Percy Shelley’s ZYXWVUTSRQPONM The Sensitive-Plant (1820) examines the species perhaps most central to the era’s investigations into vegetable movement, the M im osa pudica, a Brazilian plant that closes i. Cox, D escriptive Catalogue of the Several Superb and M agnificent Pieces of M echanism and Jewellery, Exhibited in the M useum , at Spring-G ardens, Charing-Cross (London, 1772), 25. 2. Cox, D escriptive Catalogue, 31—32. 3. For instance, Percy Shelley’s fleeting “flower that smiles today / Tomorrow dies” con­ trasts with William Blake’s time-transcending “Wild Flower” that promises “Eternity in an hour.” SiR , 56 (Summer 2017) 223 224 MELISSA BAILES and recoils its leaves when touched. In 1729, the astronomer, Jean Jacques d’Ortous de Mairan, performed the first-known experiments in chronobiology , or the study of “adaptations evolved by living organisms to cope with regular geophysical cycles in their environment,” displaying that the spontaneous daily rise and nightly fall of the sensitive plant’s leaves persist even while kept in the absence of light under constant conditions.4 Earlier naturalists noticing other species’ leafmovements described them as passive reactions to environmental stimuli, particularly the sun. De Mairan’s exper­ iments suggested that plants’ physiological rhythms may be regulated not merely by environmental factors, but from within.5 Over the course of the century, botanists improved on his work, generating new ideas about plants’ timekeeping abilities and possession of internal clockwork, or what we now call circadian rhythms, directing plants’ movements and prompt­ ing questions about the extent of their agency.6 In Shelley’s poem, vegeta­ ble species, and especially the ZYXWVUTSRQPONMLKJIHGFEDCBA M im osa pudica, sensitively interact with their environment and respond to the death of their female caretaker, ultimately becoming emblems of ephemeral beauty themselves by succumbing to sea­ sonal changes. I argue that such verse treatments of plants and flowers par­ ticipate in a larger, contemporary framework in which naturalists and poets explored and debated plants’ movements, sentiency, and timekeeping mechanisms, particularly in relation to what became known as the Floral clock. Botanical studies soared in popularity in Britain in the latter half of the eighteenth century, especially due to the Swedish naturalist, Carl Linnaeus, whose work helped inspire pervasive interest in flowers’ movements and daily times of blossoming.7 In his Philosophia Botanica (1751), Linnaeus, re­ nowned for his system ofbotanical classification that ordered plants accord­ ing to their sexual parts, proposed groundbreaking investigations into horological processes in the vegetable world. He ambitiously called for “Floral calendars” charting circannual developments of botanical species to be “completed every year in every province,” and “Floral clocks” functioning “under any climate” “to be worked out according to the watches of the plants, so that anyone can make calculation of the hour of the day without a clock or sunshine.”8 Advocating the Horologium Florae or Floral clock, 4. Jay C. Dunlap, Jennifer J. Loros, Patricia J. DeCoursey, eds., Chronobiology: Biological Tim ekeeping (Sunderland, MA: Sinauer Associates, 2004), xvii. 5. DeCoursey, “The Behavioral Ecology and Evolution of Biological Timing Systems,” in Chronobiology, 42. 6. Some of these botanists include Henri-Louis...