Barleria maclaudii Benoist (Family Acanthaceae) grows in savannah and woodland mosaics on lateritic slopes at 150–700 m altitude. Described by Raymond Benoist in 1911, it was initially discovered in Fouta-Djalon (Guinea) in 1898. Formerly, the most recent observation in Guinea was in 1936, near Dinguiraye. Additionally, it has been recorded in Senegal and Mali, with a total of 4–5 localities across these three countries. The extent of these localities is poorly understood, as they are only known from seven herbarium specimens. For these reasons, and because of known threats at some of these localities, the species is categorized as Endangered on the IUCN Red List.
However, in October 2021, after 86 years without records, B. maclaudii was rediscovered in Guinea, around the village of Kokoun Thimbobhé (sub-prefecture of Kollet), within the Moyen-Bafing National Park in Fouta-Djalon. During November 2022–June 2023, the species was recorded in c. 20 more localities in the Park, with half of these in the core protected area and high conservation value zones. The localities cover a total extent of occurrence c. 1,460 km2, and we estimate that the total known area of occupancy is at least 7 km2, with a population size of c. 8,000 individuals. The altitude range of the localities is 417–772 m, slightly exceeding the previously known upper limit.
Barleria maclaudii Benoist in Kokoun Thimbobhé (Moyen-Bafing National Park): (a) habitat and (b) inflorescence with a flower. Photos: Camille Rieder.
These new observations facilitated photographic documentation and seed and herbarium specimen collection. The species' perennial nature was confirmed: despite annual bushfires, the woody bases persist and appear to be fire-tolerant. Flowering is September–November, and the species grows on skeletal laterite soil in the understory of woodland dominated by Terminalia macroptera Guill. & Perr.
This discovery of several localities in Moyen-Bafing National Park greatly improves our knowledge of this species in Guinea. However, populations in Senegal and Mali have not been surveyed recently and the species' known minimal area of occupancy remains less than the 500 km2 threshold for categorization as Endangered. As there is an ongoing threat from slash-and-burn agriculture within the Park, and a population increase has not been documented, categorization as Endangered under criterion B2ab(ii,iii) remains appropriate pending further study.
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