Canna (or Canna lily, although not a true lily) is a genus of approximately twenty species of flowering plants. The closest living relations to cannas are the other plant families of the order Zingiberales, that is the gingers, bananas, marantas, heliconias, strelitzias, etc.
Canna is the only genus in the family Cannaceae. Such a family has almost universally been recognized by taxonomists. The APG II system of 2003 (unchanged from the APG system, 1998) also recognizes the family, and assigns it to the order Zingiberales in the clade commelinids, in the monocots.
The species have large, attractive foliage and horticulturists have turned it into a large-flowered, brash, bright and sometimes gaudy, garden plant. In addition, it is one of the world's richest starch sources, and is an agricultural plant.
Although a plant of the tropics, most cultivars have been developed in temperate climates and are easy to grow in most countries of the world as long as they can enjoy about 6 hours average sunlight during the summer. See the Canna cultivar gallery for photographs of Canna cultivars.
Cannas grow best in full sun with moderate water in well-drained rich or sandy soil. Cannas grow from perennial rhizomes but are frequently grown as annuals in temperate zones for an exotic or tropical look in the garden.
The rhizomes are marginally cold hardy but may rot if left unprotected in freezing conditions. In areas which go below about −10 °C in the winter, the rhizomes can be dug up before freezing and stored in a protected area (above +7 °C) for replanting in the spring. Otherwise, it is recommended that Cannas are protected by a thick layer of mulch overwinter.
Wild Canna species are the Cannas unaffected by mankind. There are approximately 20 known species, and in the last three decades of the 20th century, Canna species have been categorised by two different taxonomists, Paul Maas, from the Netherlands[16] and Nobuyuki Tanaka from Japan. Both reduced the number of species from the 50-100 that had been accepted previously, and assigned most to being synonyms.
The reduction in numbers is also confirmed by work done by Kress and Prince at the Smithsonian Institution, however, this only covers a subset of the species range.
* Some species and many cultivars are widely grown in the garden in temperate and sub-tropical regions. Sometimes, they are also grown as potted plants. A large number of ornamental cultivars have been developed. They can be used in herbaceous borders, tropical plantings, and as a patio or decking plant.
* Internationally, cannas are one of the most popular garden plants and a large horticultural industry depends on the plant.
* The canna rhizome is rich in starch, and it has many uses in agriculture. All of the plant has commercial value, rhizomes for starch (consumption by humans and livestock), stems and foliage for animal fodder, young shoots as a vegetable and young seeds as an addition to tortillas.
* The seeds are used as beads in jewelry.
* The seeds are used as the mobile elements of the kayamb, a musical instrument from Réunion, as well as the hosho, a gourd rattle from Zimbabwe, where the seeds are known as "hota" seeds.
* In remoter regions of India, cannas are fermented to produce alcohol.
* The plant yields a fibre - from the stem - it is used as a jute substitute.
* A fibre obtained from the leaves is used for making paper. The leaves are harvested in late summer after the plant has flowered, they are scraped to remove the outer skin and are then soaked in water for 2 hours prior to cooking. The fibres are cooked for 24 hours with lye and then beaten in a blender. They make a light tan brown paper.
* A purple dye is obtained from the seed.
* Smoke from the burning leaves is said to be insecticidal.
* Cannas are used to extract many undesirable pollutants in a wetland environment as they have a high tolerance to contaminants.
* In Thailand, Cannas are a traditional gift for Father's Day.
The first Cannas introduced to Europe were C. indica L., which was imported from the East Indies, though the species originated from the Americas. Charles de l'Ecluse, who first described and sketched C. indica indicates this origin, and states that it was given the name of indica, not because the plant is from India, in Asia, but because this species was originally transported from America: "Quia ex America primum delata sit"; and at that time, one described the tropical areas of that part of the globe as the Western Indies; English speakers still call them the West Indies.
Much later, in 1658, Pison made reference to another species which he documented under the vulgar or common name of 'Albara' and 'Pacivira', which resided, he said, in the shaded and damp places, between the tropics; this species is Canna angustifolia L., (later reclassified as C. glauca L. by taxonomists).
Without exception, all Canna species that have been introduced into Europe can be traced back to the Americas, and it can be asserted with confidence that Canna is solely an American genus. If Asia and Africa provided some of the early introductions, they were only varieties resulting from C. indica and C. glauca cultivars that have been grown for a long time in India and Africa, with both species imported from Central and South America. Canna is an American genus, as pointed out by Lamarck were he argues that "Cannas were unknown to the ancients, and that it is only after the discovery of the New World, that they made their appearance in Europe; Since Canna have very hard and durable seed coverings, it is likely that seed remains would have survived in the right conditions and found by archaeologists in the Old World. If the soils of India or Africa had produced some of them, they would have been imported before the 1860s into European gardens.
The genus is native to tropical and subtropical regions of the New World, from the southern United States (southern South Carolina west to southern Texas) and south to northern Argentina.
Although all cannas are native to the New World, they have followed mankind's journeys of discovery and some species are cultivated and naturalized in most tropical and sub-tropical regions.
Canna cultivars are grown in most countries, even those with territory above the Arctic Circle, which have short summers but long days, and the rapid growth rate of Cannas makes them a feasible gardening plant, as long as they get their 6 hours of sunlight each day during the growing season and are protected from the cold of winter.
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