Twinkling Flowers
One summer evening early in the 1960s, a young woman sat in her father’s garden enjoying the last rays of the setting sun. All of the sudden, a flash of light caught her eye. To her bewilderment, the bright orange-gold flowers nearby appeared to be flashing.
The young woman was Elizabeth Linnaeus, daughter of the famous Carl Linnaeus, the Father of Taxonomy. Although only 19 years old, she dutifully wrote down her observations and had them published in the Acts of the Royal Swedish Academy of Sciences. Her article, “On the twinkling of Indian Cress” received attention from notable members of society, including the famous physician and naturalist Erasmus Darwin, grandfather of Charles Darwin, and the romantic poets Samuel Taylor Coleridge and William Wordsworth.
The flower in question was Tropaeolum majus, also known as “Indian Cress,” appeared to shimmer in the setting sun. In her article, Elizabeth questioned if the flowers were reflecting “invisible Northern Lights” or if the phenomenon was due to the positioning of the eye. Her father and noted lecturer of the day, Johan Wilcke, both published commentaries on her article and mused whether the flowers were discharging some form of electrical energy.
Now electricity was something of a craze in the 18th century. After a hair-raising adventure flying a kite, Benjamin Franklin was running around advocating lightning rods. Simple phenomena like the production of static sparks in a darkened salon could mystify audiences. The Physician Luigi Galvani made frog muscles twitch with an electric machine and so laid the inspiration for Mary Shelly’s Frankenstein. Society was electrified!
The idea that flowers could emit electricity was lapped up by the romantics of the age. It also raised serious questions about the heretofore unregarded internal life of plants. After all, animals were animated by electrical impulses. Did plants have animal senses? Could they feel pleasure or pain? What did a flower think?
Of course, you might guess that Indian cress does not discharge electricity. The phenomenon Elizabeth observed was . . . an “after image.” The intense orange-gold of the flowers left an impression on the retina resulting in an optical illusion. The flowers appeared to shimmer.
It’s funny, because the young Miss Linnaeus was close to the truth in her article. It was only when “more learned” men imposed their ideas and fed the popular, sensational fads of the day, did a simple story about twinkling plants spiral into a philosophical debate on the emotional life of flowers.
Brian Rutter, PhD, is the cofounder of Hundredfold Video and plant biologist working for 2Blades at the University of Minnesota. Subscribe to our newsletter to receive our “Things About Things – Odd Facts About Plants” and video production tips in your inbox every month!
Works Cited:
Bertucci, Paola. "Sparks in the dark: the attraction of electricity in the eighteenth century." Endeavour 31, no. 3 (2007): 88-93.
Blick, Fred. "Flashing Flowers and Wordsworth’s “Daffodils”." The Wordsworth Circle 48, no. 2 (2017): 110-115.
