Thalia L.
Thalia is a genus with ca. 6 species in tropical America with one species extending to tropical Africa (Prince & Kress 2006, Mabberley 2008). All are marsh plants and two of them are cultivated as aquatic ornamentals in Europe: T. dealbata Fraser and T. geniculata L. (Walters & al. 1984). The former was recently found in the wild in Belgium, probably as a throw-out or a mere relic of cultivation. The second species is now also found as a naturalized alien in parts of Africa and Asia (e.g. Sijimol & al. 2000).
Literature:
Kennedy H. (2000) Marantaceae. In: Flora of North America Editorial Committee (ed.), Flora of North America, vol. 22: 315-319. Oxford University Press, New York-Oxford. [available online at: http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=10535]
Mabberley D.J. (2008) Mabberley’s plant-book (3th ed.). Cambridge University Press, Cambridge: XVIII + 1021 p.
Prince L.M. & Kress W.J. (2006) Phylogenetic relationships and classification in Marantaceae: insights from plastid DNA sequence data. Taxon 55(2): 281-296. [available online at: https://www.researchgate.net/publication/233605459_Phylogenetic_Relation...
Schumann K. (1902) Marantaceae. In: Engler A. (ed.), Das Pflanzenreich 11: 1-184. [available online at: http://www.biodiversitylibrary.org/bibliography/71436#/summary]
Sijimol P.S., Rajesh K.P. & Madhusoodanan P.V. (2000) On the occurrence of Thalia geniculata L. (Marantaceae) in India. J. Econ. Taxon. Bot. 24: 727-730.
Walters S.M., Brady A., Brickell C.D., Cullen J., Green P.S., Lewis J., Matthews V.A., Webb D.A., Yeo P.F. & Alexander J.C.M. (eds.) (1984) The European Garden Flora, vol. 2 (part II). Cambridge University Press: 318 p.