Pleistocene refugia
The entire Cameroon line is considered a Pleistocene forest refuge for its distinctive flora. Forest refugia are also supported because of the high genetic diversity detected in different trees (Pineiro et al. 2017) such as the genus Greenwayodendron (Migliore et al. 2018), and other flowering plants. For example, Arabis alpina (L.) survived the Pleistocene oscillations of temperature and drought in refugia. Once the environmental conditions changed during the interglacial periods,A. alpina colonized or recolonized new sky islands in East-Central Africa (Assefa et al. 2007).
It is possible that the populations of L. columnaris were dynamically isolated and expanded within and between the sky islands of West Central Africa. However, Pico Biao-Moka in South Bioko might be a Pleistocene forest refuge to Afromontane plant species.