Do both Butea and Calanthe have just two species?
Butea Butea is a genus of flowering plants belonging to the pea family, Fabaceae. It is sometimes considered to have only two species, "B. monosperma" and "B. superba", or is expanded to include four or five species.
Sanderella Sanderella is a genus of flowering plants from the orchid family, Orchidaceae, native to South America. Two species are recognized at present (June 2014):