Fluorescent flora

The unusual phenomenon of sparks and flame-like flashes of light emitted by certain plants remains unexplained. Many naturalists discussed it in the 19th century. This mysterious phenomenon was usually associated with species such as daisies and geraniums, meaning plants with red, orange, or yellow flowers.

In 1843, in Part II of the annual Report of the British Association, information by Richard Dowden about luminous phenomena observed in common daisies appeared:

The phenomenon was observed on August 4, 1842, at eight o'clock in the evening, after a week of dry, hot weather. Four people saw it. At sunset, a soft, golden light passed from petal to petal of the flower, creating a sort of full or occasionally broken corona around its center. The glow seemed to fade as dusk approached. Whether it occurred in darkness has not been determined. This oversight should be corrected at the first favorable opportunity. It should also be added, to facilitate the task of future observers interested in this strange phenomenon, that the best subject for the experiment is a double daisy, because the single flower "falls asleep with the sun" and therefore its petals cannot be examined.

In 1882, Louis Crie published a short note on the same subject in Scientific American.

In the case of vegetables, light emissions have been observed in a dozen open-budding plants and about fifteen earth-budding plants. The phenomenon of phosphorescence in the flowers of chrysanthemums (Pyrethrum inodorum), tuberoses (Polianthes), and pandani has long been known. Haggren and Crome were the first to discover light emanations in nasturtiums and daisies, and a few years ago I myself had the opportunity to observe the glow emitted by the flowers of nasturtiums (Tropaeolum majus), cultivated in a garden in Sarthe.

The English periodical Knowledge also published several articles in the 1880s about flowers shining with an unusual brilliance. It turned out that one of the first witnesses to this strange phenomenon was the daughter of Carl Linnaeus, the father of modern botanical and zoological systematics.

She noticed them in the summer of 1762 while examining flowers in her garden at dusk. Her later experience was described in Knowledge by Mr. S. Ingham in 1883:

Recently, I was pulling annuals from a bed where geraniums were already growing. I was surprised to see flashes of light coming from a cluster of geranium flowers. At first, I thought I was deluded, but my wife and a friend also saw the phenomenon. It happened at nine in the evening, on a cloudless day. There were also geranium flowers of a different color in the bed, but only the geraniums of the Tomcio Paluszek [Tom Thumb] variety were emitting light.

this a known phenomenon? I've never heard of it or read about it. Eleven years later, Simpkin, Marshall & Co. published a volume titled Lessons in Physical Science. The book includes the following commentary on the phenomenon:

It is likely to this same source—electricity—that we owe the light emitted at certain times of the year and day by yellow or orange flowers, such as daisies, sunflowers, and gladioli. Several naturalists witnessed this phenomenon. The flower emitted light of varying intensity, in rapid succession. At other times, small sparks jumped from flower to flower, several minutes apart.

The idea that some flowers are capable of visible light emission is undoubtedly shocking. However, it is possible to explain the phenomenon as a peculiar optical effect, caused by the reflection of sunlight by petals of a specific color, acting like miniature mirrors (this explains why the effect fades with the onset of dusk).

Regardless of the answer, flowers emitting light rays are currently a forgotten botanical phenomenon. Researchers either don't study this mystery or are completely unaware of it. However, early naturalists knew about it and even witnessed it. It's high time for the younger generation to rediscover these forgotten mysteries and contribute to their explanation. After all, as Mark Chorvinsky so eloquently stated, " There's no shortage of daisies and geraniums in the world."