A potentially large, deciduous tree endemic to southern China, bearing large racemes of scented white flowers, with conspicuous white, leaf-like structures (calycophylls) scattered through the inflorescence.
Emmenopterys, as currently understood (Chen & Taylor 2011a), has just one living species. However, fossil infructescences of an extinct species are found in the Clarno Nut Beds of Oregon (Eocene, c. 44 million years ago), and similar-looking fossils are known from Middle Eocene deposits in Germany (Manchester et al. 2009). It seems that Emmenopterys is a classic example of a Tertiary relict genus. Such groups were widely distributed across the northern continents in the early part of the Tertiary era. Changing climates subsequently restricted their ranges, usually to areas within East Asia (Milne & Abbott 2002).
The generic name derives from the Greek emmeno (remain) and pteron (feather or wing), and refers to the calycophylls, the curious white leaf- or bract-like structures scattered through the inflorescence, derived from an expanded calyx-lobe. To European eyes these features of various members of the Rubiaceae (for example the tropical genus Mussaenda) are exotic structures. Emmenopterys henryi is one of only a tiny number of hardy trees to have them. The enlarged, petaloid sepal of a sterile flower within a Schizophragma inflorescence is a close and more familiar parallel.
A second species, E. rehderi F.P. Metcalf, is now usually treated as a synonym of Schizomussaenda dehiscens (Craib) H.L. Li, following Flora of China, but the name is still encountered. S. dehiscens is a smaller tree or shrub, with a narrower distribution in southern China, extending south into neighbouring countries. It is not known to be in cultivation.