Canna L.
As currently understood Canna is a small genus of 10 species that are originally native in (sub-) tropical America (Maas-van de Kamer & Maas 2008). Some authors formerly applied a much narrower species concept (especially in the C. indica group) and recognized more than 50 species (Kress & Prince 2000). Several species and hybrids are grown for their striking foliage and large, delicate flowers. As a result of hybridization and selection plants in cultivation are not easily identified nowadays. They are usually of complex hybrid origin and are here ascribed to Canna xgeneralis. This nothotaxon is a cross of uncertain parentage, probably C. indica L. x C. glauca L. or C. indica x C. iridiflora Ruiz & Pav. (Donahue 1965). Further crosses of this hybrid with C. flaccida Salisb. have been referred to C. xorchioides L. Bailey (Mabberley 2008). Additional taxa might be in cultivation as well (see for instance Ratter 1984, Kress & Prince 2000). Jäger & al. (2008) cite four species that are grown as ornamentals in Central Europe: C. indiflora Ruiz & Pav., C. flaccida, C. glauca and C. indica. All are frost-sensitive and probably not hardy in our area. Some of the plants found in the wild in Belgium are obviously hardy and this may also point at selected cultivars/hybrids.
Literature:
Donahue J.W. (1965) History, breeding and cultivation of the canna. Amer. Hort. Mag. 44: 84-91.
Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.
Khoshoo T.N. & Guha I. (1976) Origin and evolution of cultivated cannas. New Dehli: Vikas Publishing House.
Kress W.J. & Prince L.M. (2000) Cannaceae. In: Flora of North America Editorial Committee (eds.), Flora of North America, vol. 22. Oxford University Press, New York-Oxford: 310-314. [available online at: http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=10155]
Maas-van de Kamer H. & Maas P.J.M. (2008) The Cannaceae of the world. Blumea 53: 247-318. [available online at: http://repository.naturalis.nl/document/564893]
Mabberley D.J. (2008) Mabberley’s plant-book (3th ed.). Cambridge University Press, Cambridge: XVIII + 1021 p.
Prince L.M. (2010) Phylogenetic Relationships and Species Delimitation in Canna (Cannaceae). In Seberg & al., Diversity, phylogeny and evolution in the monocotyledons. Aarhus University Press, Denmark: 307-331. [available online at: http://www.rsabg.org/documents/research/lprince/Prince_2010.pdf]
Ratter J.A. (1984) Canna. In: Walters S.M. & al. (eds.), The European Garden Flora, vol. 2: 129-130. Cambridge University Press, Cambridge.
Segeren W. & Maas P.J.M. (1971) The genus Canna in northern South America. Acta Bot. Neerl. 20: 663-680. [available online at: http://natuurtijdschriften.nl/search?identifier=539807]
Tanaka N. (2001) Taxonomic revision of the family Cannaceae in the New World and Asia. Makinoa N.S. 1: 1-74.