Oxygyne Schlechter

The genus was established by Schlechter (1906) when he discovered the distinct feature of only three stamens instead of six, along with the general floral characteristics of the tribe Thismieae. The type locality ("Kamerun: ... Urwalde bei Moliwe" = native forest close to Molive/Cameroon) is destroyed, the type species, Oxygyne triandra (R. Schlechter 15700, flowering in September 1905), has never been found again since its discovery. A peculiar disjunction is present in this genus with three species from western central Africa (Cameroon and Central African Republic) and three species from Japanese islands. There has been attempts to separate the disjunct groups of the genus into Saionia (Japanese species) and Oxygyne (African species) by Hatusima (1975, Flora of the Ryukyus, added and corrected. Naha: Okinawa Association of Biology Education (in Japanese), cited after Cheek et al. 2018) as well as Hatusima (1976) and later by Ohashi (2015). However, apart from the fact that the description of Saionia was not validly published due to (1) lack of latin diagnosis (in Hatusima 1975),  and (2) for the citation of two holotype specimen (T. Shinzatoi s.n. 1972 and T. Shinzatoi s.n. 1974) in Hatusima (1976), the presumably distintive features between the Japanese and African Oxygyne turned out to occur in both groups, namely in the recently described Oxygyne duncanii (Cheek et al. 2018). I recommend the comprehensive synopsis of the genus Oxygyne by Cheek et al. (2018) for further information.