A new cloud forest treeLychnodiscus bali(Sapindaceae), Critically Endangered from the Bali-Ngemba Forest reserve, N.W. Region, Cameroon

Summary We describe Lychnodiscus bali (Sapindaceae) a new species to science, from the Bali Ngemba Forest Reserve of NW Region Cameroon, the last major remnant of cloud forest in the Bamenda Highlands of Cameroon, recently evidenced as a Tropical Important Plant Area (TIPA or IPA). Confined on current evidence to upper submontane forest, the species is threatened by expanding habitat clearance for farms and is assessed as Critically Endangered. A small tree, attaining 3 – 4 m height, it is the first new species to be added to this Guineo-Congolian tree genus in 50 years, the third recorded from Cameroon, and takes the number of species in the genus to eight. It has the highest known altitudinal range (1700 – 1950 m alt.), of any species of the genus. Previously identified as Lychnodiscus grandifolius , the new species differs in the shorter length of the distal leaflets (12 – 18 cm vs 22 – 39 cm long), in the abaxial surface lacking glands (vs glands flat and conspicuous), tertiary nerves hairy (vs glabrous), flowers at anthesis 8 – 11 mm long (vs 5 – 7 mm long). Lychnodiscus bali is described, illustrated and its extinction risk assessment as Critically Endangered is presented. We discuss its discovery in the context of other recently discovered and highly threatened or even extinct plant species in the Cameroon Highlands, and the importance of their conservation. We present an updated key to the identification of the species of the genus,and discuss its classification in the context of recent molecular phylogenomic studies. Previously placed in Cupanieae by Radlkofer, the authors contend that Lychnodiscus should now be placed in the reconstituted Nepheliaeae in the revised 2021 intrafamilial classification of Buerki et al., probably close to the genera Aporrhiza and Laccodiscus . However, until the genus is included in molecular studies this cannot be confirmed and its sister relationship remains speculative.