Rubrivena M. Král
Rubrivena, as currently understood (see Galasso & al. 2009), is a genus of two species, both native to Asia. One, Rubrivena polystachya, is sometimes cultivated as an ornamental (perhaps less so nowadays).
In the past decades species of Rubrivena have been attributed mostly to the genera Persicaria or Aconogonon. Morphologically, Rubrivena doubtlessly is more closely similar to Aconogonon. Molecular phylogenetic research also proved a closer relationship to the latter (Galasso & al. 2009). On the other hand, pollen character of Rubrivena and Persicaria are similar. More recent molecular data, on the contrary, showed Rubrivena to be best merged with Aconogonon and Koenigia, the latter genus being the oldest and having priority (Schuster & al. 2015). A more conservative approach is adopted, however, in this account.
Literature:
Galasso G., Banfi E., De Mattia F., Grassi F., Sgorbati S. & Labra M. (2009) Molecular phylogeny of Polygonum L. s.l. (Polygonoideae, Polygonaceae), focusing on European taxa: preliminary results and systematic considerations based on rbcL plastidial sequence data. Atti Soc. It. Sci. Nat. Museo Civ. Stor. Nat. Milano 150(1): 113-148.
Hong S.-P. (1993) Reconsideration of the generic status of Rubrivena (Polygonaceae, Persicarieae). Pl. Syst. Evol. 186(1-2): 95-122.
Král M. (1985) Rubrivena, a new genus of Polygonaceae. Preslia 57(1): 65-67.
Schuster T.M., Reveal J., Bayly M. & Kron K.A. (2015) An updated molecular phylogeny of Polygonoideae (Polygonaceae): Relationships of Oxygonum, Pteroxygonum, and Rumex, and a new circumscription of Koenigia. Taxon 64(6): 1188-1208. [available online at: https://www.researchgate.net/publication/288889005_An_updated_molecular_...