Frankfurt am Main | 12 – 20 October 2024

Anno Oxypetalum

Art United Kingdom 2023
By Anna Ridler
Anno oxypetalum (literally “the year of the pointed petals”) is a clock made of the flowers of night-blooming cacti, tracking the amount of light across one year. Each flower represents 10 minutes, each second approximately 2 days. Over the course of the piece the flowers fade in and out as the light ebbs and flows across the seasons. The timing of dawn and dusk is precisely accurate for London starting at the 2021 winter solstice. A third level of time is also incorporated into the work - when the piece is sold, the smart contract is programmed to start the video at the beginning of the season in which it was sold. The smart contract is able to accurately compute the solstices and equinoxes until the year 3000. It is inspired by plants’ chrono-biological clocks, by which they bloom and close at fixed times of day. Plants behave this way regardless of external stimuli - a night-blooming cactus, for example, will only bloom at night, even if it is exposed to darkness during the daytime and light at night; a morning glory moved into permanent darkness will still flower in the mornings. The work call backs to Carl Linnaeus’ idea of a horologium florae or floral clock, proposed in his Philosophia Botanica in 1751 after observing the phenomenon of certain flowers opening and closing at set times of the day, and harkens back to an earlier, medieval way of delineating time according to the amount of daylight present, before the advent of modern timekeeping.


Film Info


Anno Oxypetalum
Original title
Anno Oxypetalum
Release Date
  • United Kingdom




  • Anna Ridler

    Anna Ridler (b. 1985) is an artist and researcher who works with systems of knowledge and how technologies are created in order to better understand the world. She is particularly interested in ideas around measurement and quantification and how this relates to the natural world. Her process often involves working with collections of information or data, particularly datasets, to create new and unusual narratives

    Ridler holds an MA in Information Experience Design from the Royal College of Art and a BA in English Literature and Language from Oxford University along with fellowships at the Creative Computing Institute at University of the Arts London (UAL). Her work has been exhibited at cultural institutions worldwide including the Victoria and Albert Museum, the Barbican Centre, Centre Pompidou, HeK Basel, the ZKM Karlsruhe, Ars Electronica, Sheffield Documentary Festival and the Leverhulme Centre for Future Intelligence. She was a European Union EMAP fellow and the winner of the 2018-2019 DARE Art Prize. In 2018 she was listed as one of the nine “pioneering artists” exploring AI’s creative potential by Artnet.

    Ridler lives and works in London.

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