Emmenopterys Oliver

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Julian Sutton (2019)

Recommended citation
Sutton, J. (2019), 'Emmenopterys' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/emmenopterys/). Accessed 2021-02-24.


  • Rubiaceae

Species in genus


Dry indehiscent single-seeded fruit with woody outer wall.
Reduced leaf often subtending flower or inflorescence.
(pl. calyces) Outer whorl of the perianth. Composed of several sepals.
IUCN Red List conservation category: ‘there is no reasonable doubt that the last individual [of taxon] has died’.
Flower-bearing part of a plant; arrangement of flowers on the floral axis.
Division of a leaf or other object. lobed Bearing lobes.
Petal-like. May refer to sepals or stamens modified into a petal-like form.
Single segment of the calyx. Protects the flower in bud.
(syn.) (botanical) An alternative or former name for a taxon usually considered to be invalid (often given in brackets). Synonyms arise when a taxon has been described more than once (the prior name usually being the one accepted as correct) or if an article of the International Code of Botanical Nomenclature has been contravened requiring the publishing of a new name. Developments in taxonomic thought may be reflected in an increasing list of synonyms as generic or specific concepts change over time.


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Julian Sutton (2019)

Recommended citation
Sutton, J. (2019), 'Emmenopterys' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/emmenopterys/). Accessed 2021-02-24.

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.