Pontederia natans P.Beauv., Fl. Oware 2: 18. 1807.

Pellegrini, Marco O. O., Horn, Charles N. & Almeida, Rafael F., 2018, Total evidence phylogeny of Pontederiaceae (Commelinales) sheds light on the necessity of its recircumscription and synopsis of Pontederia L., PhytoKeys 108, pp. 25-83 : 25

4.4. Pontederia natans P.Beauv., Fl. Oware 2: 18. 1807.

Eichhornia natans (P.Beauv.) Solms, Abh. Naturwiss. Vereins Bremen 7: 254. 1882.

Leptosomus natans (P.Beauv.) Schltdl., Abh. Naturf. Ges. Halle 6: 174. 1862. Lectotype (designated here). NIGERIA. Benin, fleuve Formosa, fl., fr., s.dat., A.M.F. Palisot de Beauvois s.n. (G on 3ex barcode G00418251!; isolectotype: G-DC on 4ex GDC048496!).

Distribution.

Angola, Benin, Botswana, Burkina Faso, Cameroon, Central African Republic, Chad, Congo, Egypt, Ethiopia, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Madagascar, Mali, Mozambique, Niger, Nigeria, Rwanda, Senegal, Sierra Leone, South Sudan, Sudan, Tanzania, Togo, Uganda, Zaire, Zambia and Zimbabwe.

Nomenclatural notes.

When describing P. natans , Palisot de Beauvois (1807) comments that his new species is common at the margins of the Formosa River (currently called Benin River). After analysing specimens from G and G-DC herbarium, we came across two specimens, mounted on seven sheets. The specimen GDC048496 is mounted on four sheets, composed of several flowering and fruiting specimens, with an extremely detailed annotation in the handwriting of Palisot de Beauvois. Nonetheless, the specimen G00418251 is mounted on three sheets, with the second sheet possessing a detached petiolate leaf and a copy of the original illustration and the third possessing the specimen on which the illustration was based. Thus, the G00418251 specimen is the obvious choice for a lectotype.

Taxonomical notes.

The African E. natans (≡ P. natans ) is currently treated as a synonym of the Neotropical Eichhornia diversifolia (≡ P. diversifolia ) by all online databases (i.e. eMonocot 2010; The Plant List 2013; Govaerts 2018; Tropicos.org 2018). Nonetheless, as indicated in our identification key (see above), both species can be easily differentiated based on the number of flowers per inflorescence, floral diameter, presence or absence of a nectar guide, pubescence of the filaments and capsule dehiscence. Thus, P. natans is here re-established.