Canna tuerckheimii Kraenzl.

A giant species; green foliage, oblong shaped, branching habit; spikes of flowers are erect, self-coloured crimson, staminodes are long and narrow, edges regular, petals purple, fully self-cleaning; fertile both ways, not self-pollinating or true to type, capsules ellipsoid; rhizomes are thick, up to 7 cm in diameter, coloured white and purple; tillering is prolific.

Introduced by Kraenzl. Native of Belize, Costa Rica, Guatemala, Honduras, Mexico, Nicaragua, Panama, Colombia and Ecuador at altitudes of 500-2,000m (1,600 – 6,500ft). Johnson’s Dictionary of 1856 reports that it first entered England in 1820 as Canna latifolia, meaning ‘broad-leaved’.

Professor Paul Maas and his wife Dr. Hiltje Maas, consider C. tuerckheimii is the correct name, but Dr. Nobuyuki Tanaka considers that the correct name is C. latifolia.

Synonyms: C. altensteinii Bouché, C. ‘Broadleaf’, C. ‘Broad-leaved canna’, C. coccinea var. sylvestris (Roscoe) Regel, C. curviflora Horan., C. gemella Nees & Mart., C. gigantea F. Delaroche, C. iridiflora Willd., C. latifolia Mill., C. macrophylla Hort. ex Horan., C. ‘Marabout’, C. neglecta Weinm., C. sylvestris Roscoe, C. violacea Bouché

Canna tuerckheimii to be conserved

A proposal has been made to conserve the name Canna tuerckheimii against C. latifolia, C. gigantea, C. neglecta, and C. violacea and the name C. jaegeriana against C. leucocarpa (Cannaceae). The proposal has been made by Dr. Hilte Maas van der Kamer, of the National Herbarium, Netherlands in the journal TAXON.

Most of the proposal is devoted to the C. tuerckheimii proposition and what look like totally convincing arguments are made for the proposition that C. latifolia, C. gigantea, C. neglecta, and C. violacea should be synonyms of C. tuerckheimii.

However, Dr Tanaka, in his revision of the species, put forward his view that C. tuerckheimii was a synonym of C. latifolia.

Interestingly, one of the arguments put forwards refers to the number of Google hits under the various names. The times, they are a changin’, even for taxonomists.

The proposition for C. jaegeriana looks less controversial, and as Dr Tanaka also recognises C. jaegeriana it would appear that proposition may pass without question. However, this is not a two-man show and there are others involved other than our two learned species authorities.

As we have happily grown and spelt C. latifolia for many years we are concerned about a change in name to one we cannot spell! More seriously, it is good to see how the naming process works, as the canna genus still has many ‘old species’ to classify and align.