A rare plant native to northern Africa has been declared extinct after an exhaustive five-year search failed to turn up any sign of its continued existence.

Known only by its scientific name, Adenocarpus faurei, this yellow-flowering shrub was native to the Oued Sidi Khaled valleys of northern Algeria, where it lived at altitudes of around 3,600 feet. It was first described scientifically in 1926—which, coincidentally, was the last time it was ever officially seen.

That didn’t stop people from looking. Most recently, researchers from Algeria’s University Ibn Khaldoun—located in the city of Tiaret, near where the plant once lived—started a search for Adenocarpus faurei in 2009. They then conducted a thorough exploration from 2012 through 2017, systematically covering the entire forested area around Tiaret.

Their searches revealed a highly degraded habitat but turned up none of the missing plants, as they described in a paper published April 26 in The Journal of Threatened Taxa:

This survey was not successful in finding Adenocarpus faurei. Since the region remains highly influenced by human activities, with the extension of habitations, intensive grazing and pollution being of major concern the observed threats reinforces the hypothesis of possible extinction for this plant.

Researchers tend to be careful in their language, so they aren’t quite going so far as to declare this plant’s extinction definitively—but prospects aren’t good. Meanwhile, they warn that Adenocarpus faurei’s fate could be shared by other endemic Algerian plants, which have been understudied since the country’s independence in 1962. They write: “Research on these endemic, rare and localized plants is deficient and their conservation status, or even their existence, is not well known. In Algeria and the neighboring countries of northern Africa, several similar species may be extinct in areas that are poorly protected or even neglected by responsible authorities.”

The authors say the likely loss of Adenocarpus faurei should serve as a bit of a wake-up call. “These results present a reminder for the need for novel and up-to-date field data when generating conservation assessments of the rare and endemic plants of Algeria and elsewhere,” their paper concludes. “The protection of their natural habitats remains a priority.”

This post first appeared on The Revelator on May 4, 2018.