More than 150 years after Charles Darwin first wondered whether certain sticky-leaved Saxifraga plants might be secretly carnivorous, Kunming Institute of Botany researcher Tao Deng and colleagues say they have finally confirmed it, though not in the species Darwin studied, but in a close relative found clinging to rock crevices high in the mountains of southwestern China.
Morphology of Saxifraga candelabrum. Image credit: Zhang et al., doi: 10.1038/s41467-026-75288-y.
Carnivorous plants can obtain nutrients (mainly nitrogen) by actively attracting, capturing, and ultimately digesting a diverse array of small animals.
Understanding how carnivory has independently arisen under physiological and ecological constraints has long fascinated biologists.
Carnivory has evolved multiple times in flowering plants, including members of 14 families.
Carnivorous plants are mainly placed into five major categories based on their trap type, including the widely recognized pitfall trap in pitcher plants, snap trap in Venus flytraps, sticky flypaper trap in sundews, suction trap in bladderworts, and the eel-trap or lobster-trap in corkscrew plants.
In his 1875 book Insectivorous plants, Charles Darwin proposed that two European species from the genus Saxifraga might trap and use insects, based on their sticky, hair-covered leaves.
His own feeding experiments, however, were inconclusive, and the idea was largely set aside for more than a century.
“Inspired by his work on carnivory in Drosera, Darwin proposed that two Saxifraga species — Saxifraga rotundifolia and Saxifraga umbrosa — might similarly exhibit carnivorous behavior,” Dr. Deng and co-authors said.
“Darwin regarded these two species as representing one of the most intriguing cases among plants with glandular hairs.”
“Although Darwin attempted to test this hypothesis through feeding experiments, these early attempts did not yield conclusive results.”
“The lack of conclusive evidence has prevented researchers from classifying these Saxifraga species as true carnivorous plants.”
Multiple lines of evidence for carnivory in Saxifraga candelabrum. Image credit: Zhang et al., doi: 10.1038/s41467-026-75288-y.
In their research, the authors focused on another member of the genus — Saxifraga candelabrum, a small perennial herb that grows in nutrient-poor cliffs of the Qinghai-Tibet Plateau and Hengduan Mountains.
Field surveys and an examination of 45 herbarium specimens collected between 1888 and 2016 showed that trapped insects — mostly small non-biting midges — were present on the plant’s glandular hairs in the vast majority of samples, indicating the behavior is longstanding and widespread rather than incidental.