Neotropical Cannaceae

Description

Perennial, often large-sized, glabrous herbs, with rhizomes. Stems unbranched. Leaves distichously to spirally arranged, with open sheath, without ligula. Lamina with closely set, pinnately arranged, parallel secondary veins, lower side glaucous or lanuginose, or glabrous. Inflorescence terminal, bracteate, a sympodially branched thyrse, with 2- or 1-flowered cincinni. Flowers asymmetric; sepals 3, free; corolla composed of 3 unequal petals, basally connate into a tube; androecium essentially composed of two 3-merous whorls, the inner whorl composed of 1 petaloid stamen, the staminode (previously called 'labellum'), and often a second inner staminode, the outer whorl composed of 0--2 staminodes; staminodes petaloid, varying in number; fertile stamen petaloid, with a solitary monothecal, 2-sporangiate, marginal anther; style petaloid, stigmatic areas terminal and marginal; floral tube formed by the connate parts of petals, staminodes, stamen, and style; ovary inferior, 3-locular, with numerous, anatropous ovules arranged on axile placentae, septal nectaries 3, opening by holes into the base of the floral tube. Fruit a capsule, crowned by the persistent sepals, loculicidally dehiscent or seeds released by the breakdown of the capsule wall, wall tuberculate (warty). Seeds numerous, without an aril, with a so-called imbibition lid.

Notes on delimitation

• The family of Cannaceae is placed in the order of the Zingiberales, together with Marantaceae, Costaceae, and Zingiberaceae.
  

Distribution in the Neotropics

• An originally Neotropical family with the single genus Canna L. Widely cultivated all over the Tropics and Subtropics, and often escaped and naturalized.

Distinguishing characters (always present)

• Rhizomatous herbs with open sheaths, but without ligule.
• Flowers asymmetric.
• 3 sepals.
• 3 petals.
• Varying number of staminodes, 1 fertile, petaloid  stamen with 1 monothecal anther, and 1 petaloid style.
• Fruit a loculicidal capsule with a tuberculate (warty) wall and many globose very hard seeds.
• Seeds germinating by a so-called imbibition lid, a character unique in the Plant Kingdom (see Graven et al. 1997).

Other important characters

• The species of Canna are devoid of hairs, but often the leaves, sheaths, inflorescence, bracts, and sepals are described as glaucous or woolly, scurfy, lanuginose, or waxy. This aspect is caused by an epicuticular wax layer.
• The inflorescence is sympodially branched and provided with different types of bracts: primary bracts, branch bracts, floral bracts, and bracteoles (see Maas-van de Kramer & Maas, 2008).

Key differences from similar families

Cannaceae differ from other large-stemmed Monocots by their:

• Asymmetric flowers.
• Single, petaloid stamen with a monothecal anther.

Number of genera

• Canna (10 spp.).

Status

• Canna - native.

General notes

• Many species of Canna are cultivated in the Neotropics and even naturalized.

Important literature

Graven, P., C.G. De Koster, J.J. Boon & F. Bouman.1997. Functional aspects of mature seed coat of the Cannaceae. Pl. Syst. Evol. 205: 223-240.

Kubitzki, K. 1998. Cannaceae. In: K. Kubitzki  (ed.), The families and genera of vascular plants 4: 103-106.

Maas-van de Kamer, H. & P.J.M. Maas. 2008. The Cannaceae of the World. Blumea 53: 247-318. 

How to cite

Maas-van de Kamer, H. & Maas, P.J.M. (2009). Neotropical Cannaceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Cannaceae.htm.