Revision of the Thalia geniculata complex (Marantaceae)

Within the Thalia geniculata complex, which corresponds to subgen. Arthrothalia Schum., three species have been recognized in recent taxonomic literature, viz. T. geniculata L., T. trichocalyx Gagnepain, and T. welwitschii Ridley. The variation pattern within this complex has been analyzed with the aid of pictorialized scatter diagrams and it is concluded that the entire complex is made up of a single polymorphic species, of which no further subdivision is justified. T. geniculata is redescribed and full synonymy is given.