Swingle & Tanaka.
Clymenia is a small genus of flowering plants in the family Rutaceae. There are two species included in the genus: Clymenia platypoda and Clymenia polyandra. Clymenia is now often considered to belong within the Citrus genus, because it clusters within the tribe Citreae; excluding it might make Citrus polyphyletic.
Cultivated locally for its sweet fruits on a handful of southwestern Pacific islands, Clymenia was originally considered an obscure citrus hybrid. Botanist Tyôzaburô Tanaka noted that Clymenia would hybridize with a few other citrus plants (notably kumquats), but otherwise was generally different from other citrus in many aspects of its appearance.
In the 1960s, botanist Walter Tennyson Swingle proposed that Clymenia might belong to a genus of its own.
Native to a handful of locations on Papua New Guinea and nearby islets, Clymenia is far more tropical than true citrus, and even in subtropical parts of the United States, it can only be grown in a greenhouse. Specimens planted out in Riverside, California thrived in greenhouses, but perished when planted out in the arid climate. Swingle assumed that Clymenia and citrus evolved from a single common ancestor.
Clymenia forms a shrub or small tree, free of spines. Leaves feature a short, narrow petiole, which sets them apart from most other citrus, especially the papedas native to the same general area.
Clymenia fruits are a small hesperidium, very similar to a citrus fruit. Sweet and lemony in flavor, the tangerine-sized fruits are highly segmented, with yellow pulp, and a leathery rind, similar to a true citrus fruit. They contain a large number of polyembryonic seeds. They are locally cultivated in indigenous villages, but have never been commercially cultivated.
- Andrés García Lor (2013). Organización de la diversidad genética de los cítricos (PDF) (Thesis). p. 79.
- Jorma Koskinen and Sylvain Jousse. "Citrus Pages / Distant Citrus relatives". free.fr.