Canna indica, commonly known as Indian shot,<ref name=PLANTS>Template:PLANTS</ref> African arrowroot, edible canna, purple arrowroot, Sierra Leone arrowroot,<ref name=GRIN>Template:GRIN</ref> is a plant species in the family Cannaceae. It is native to much of South America, Central America, the West Indies, Mexico, and the southeastern United States (Florida, Texas, Louisiana, and South Carolina). It is also naturalized in much of Europe, sub-Saharan Africa, Southeast Asia, and Oceania.
Canna indica is a perennial growing to between 0.5 m and 2.5 m, depending on the variety. It is hardy to zone 10 and is frost tender. The flowers are hermaphrodite.<ref>Johnson's Gardeners Dictionary, 1856</ref><ref name=chate>Chaté, E. (1867) Le Canna, son histoire, son culture. Libraire Centrale d'Agriculture et de Jardinage.</ref><ref name=khoshoo>Khoshoo, T.N. & Guha, I. - Origin and Evolution of Cultivated Cannas. Vikas Publishing House.</ref><ref name=cooke>Cooke, Ian, 2001. The Gardener's Guide to Growing cannas, Timber Press. Template:ISBN</ref> Canna indica sps. can be used for the treatment of industrial waste waters through constructed wetlands. It is effective for the removal of high organic load, color and chlorinated organic compounds from paper mill wastewater.<ref>Choudhary et al. (2011) Performance of constructed wetland for the treatment of pulp and paper mill wastewater, Proceedings of World Environmental and Water Resources Congress 2011: Bearing Knowledge for Sustainability, Palm Springs, California, USA, p-4856-4865, 22–26 May.</ref>
Canna indica (achira in Latin America,<ref name=GRIN/> cana-da-índia in Brazil) has been a minor food crop cultivated by indigenous peoples of the Americas for thousands of years.
The seeds are small, globular, black pellets, hard and dense enough to sink in water.<ref name=khoshoo/> They resemble shotgun pellets giving rise to the plant's common name of Indian shot.<ref name=PLANTS/><ref name=BBC>Seeds fired from a shotgun, BBC, 9 February 2012. Retrieved 27 August 2012.</ref> The seeds are hard enough to shoot through wood and still survive and later germinate. According to the BBC "The story goes that during the Indian Mutiny of the 19th century, soldiers used the seeds of a Canna indica when they ran out of bullets."<ref name=BBC/>
The seeds are widely used for jewellery. The seeds are also 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 the last three decades of the 20th century, Canna species have been categorised by two different taxonomists, Paulus Johannes Maria Maas from the Netherlands and Nobuyuki Tanaka from Japan. Maas regards C. coccinea, C. compacta, C. discolor, C. patens and C. speciosa as synonyms or varieties of C. indica, while Tanaka recognises several additional varieties of C. indica.
- Canna indica var. indica L.
- A medium sized species; green foliage, oblong shaped, spreading habit; triangular flower stems, coloured green; spikes of flowers are erect, self-coloured red, staminodes are long and narrow, edges regular, petals red, partial self-cleaning; fertile both ways, self-pollinating and also true to type, capsules globose; rhizomes are thick, up to 3 cm in diameter, coloured purple; tillering is prolific. Introduced by Linnaeus.<ref name=khoshoo/><ref name=tanaka>Tanaka, N. 2001. Taxonomic revision of the family Cannaceae in the New World and Asia. Makinoa ser. 2, 1:34–43.</ref>
- Canna indica var. flava (Roscoe ex Baker) Nb. Tanaka
- Yellow bloom. Many plants previously offered as C. lutea fall into this sub-species.<ref name=tanaka/>
- Canna indica var. maculata (Hook) Nb. Tanaka
- A medium sized species; green foliage, ovoid shaped, branching habit; spikes of flowers are erect, yellow with red spots, staminodes are long and narrow, edges regular, petals green, fully self-cleaning, low bloomer; fertile both ways, self-pollinating and also true to type, capsules globose; rhizomes are thick, up to 3 cm in diameter, coloured white and pink; tillering is average. Introduced by Hook.. Many plants previously offered as Canna lutea fall into this sub-species.<ref name=tanaka/>
- Canna indica var. sanctae rosea (Kraenzl) Nb. Tanaka
- A small species; green foliage, oval shaped, white margin, branching habit; spikes of flowers are erect, self-coloured pink, staminodes are long and narrow, edges regular, labellum is pink, stamen is pink, style is pink, petals red with farina, fully self-cleaning; fertile both ways, self-pollinating and also true to type, capsules ellipsoid; rhizomes are thick, up to 3 cm in diameter, coloured white and pink; tillering is prolific.<ref name=tanaka/>
- Canna indica var. warszewiczii (A.Dietr.) Nb.Tanaka
- This variety is distinguishable from C. indica var. indica by having purple-red-margined leaves, purple-red fruits and slightly corm-like thickened terrestrial stem at the base. Additionally to this, there are normally two staminodes, recurved backwards, and the stamen is often strongly reflexed at the apex. These characteristics are fairly stable in this taxon. Sometimes, this variety is confused with C. discolor Lindl., from which it differs in much smaller, deep-red coloured flowers, short and slender rhizomes and chromosome numbers (2n=27 in C. discolor and 2n=18 in C. indica var. warszewiczii)<ref name=tanaka/>
As foodThe C. indica (achira) rhizomes are large, up to Template:Convert in length, and edible.<ref>FAO, "Canna edulis", accessed 23 Feb 2016.</ref> They can be eaten raw, but are usually baked. Cooked, the rhizomes become translucent, mucilaginous, and sweet. Starch is produced by grinding or pounding the roots and soaking them in water, separating the starch granules from fibers in the roots. The starch granules of C. indica are also translucent and the largest known from any plant. The starch is occasionally marketed commercially as "arrowroot", a name also applied to the starch of other similar roots crops such as Maranta arundinacea.<ref>Lost Crops of the Incas: Little-known Plants of the Andes with Promise for Worldwide Cultivation, National Academies Press, Nation Research Council, p. 27, , accessed 22 Feb 2016.</ref> It was an ingredient in mid-nineteenth century recipes such as cakes<ref>Template:Cite book</ref> and was called tout-les-mois.<ref>Template:Cite web</ref>
The Spanish took notice of achira in 1549 when it was mentioned as one of four root crops being grown for food by the people of the Chuquimayo valley (Jaén province) of Peru. The other three were sweet potato (Ipomoea batatas), cassava (Manihot esculenta), and racacha (Arracacia xanthorrhiza). In 1609, achira was described by a Spanish visitor to Cusco, Peru.<ref>Ugent, Donald, Pozorski, Shelia, and Pozorski, Thomas (Oct-Dec 1984), "New Evidence for Ancient Cultivation of Canna edulis in Peru", Economic Botany, Vol 38, No. 4, p. 418</ref> In modern times, achira is rarely grown for food, although in the 1960s it was still an important crop in Paruro Province on the upper Apurimac River near Cusco. There, at elevations of up to Template:Convert, achira is cultivated and harvested, especially to be eaten during the Festival of Corpus Christi in May or June. The achira rhizomes are wrapped with achira leaves and placed in a pit with heated rocks. The pit is then filled with dirt and the achira is slowly baked underground.<ref>Gade, Daniel W. (1966), "Achira, the Edible Canna, Its Cultivation and Use in the Peruvian Andes," Economic Botany, Vol 20, No. 4, pp. 409-413</ref>
Canna indica (achira) has been cultivated by indigenous peoples of the Americas in tropical America for thousands of years. The place of the first domestication may have been the northern Andes, as may be true of other similar root crops such as Calathea allouia and M. arundinacea. The Cauca river valley of Colombia was a center of early domestication. Archaeological evidence has been found of the cultivation of achira in 3000 BCE by people of the Las Vegas culture of coastal Ecuador. As the Las Vegas region is arid and semi-arid, achira was not likely a native plant, but imported from more humid climates.<ref>Piperno, Dolores R. (Oct 2011), "The Origins of Plant Cultivation and Domestication in the New World Tropics", Current Anthropology, Vol 52, No. S4, pp. S457-S458. Downloaded from JSTOR.</ref> Achira was also being cultivated by 2000 BCE by the people of the Casma/Sechin culture in the extremely arid region of coastal Peru, also an area in which achira was probably not native.<ref>Ugent et al, p. 417</ref>
In modern times, C. indica is reportedly naturalized in Austria, Portugal, Spain, Azores, Canary Islands, Cape Verde, Madeira, most of tropical Africa, Ascension Island, St. Helena, Madagascar, China, Japan, Taiwan, the Bonin Islands, India, Nepal, Sri Lanka, Cambodia, Laos, Thailand, Vietnam, Burma, Java, Malaysia, the Philippines, Christmas Island, the Bismarck Archipelago, Norfolk Island, New South Wales, Queensland, Fiji, Tonga, Vanuatu, Kiribati, the Cook Islands, the Society Islands, the Caroline Islands and Hawaii.<ref>Template:WCSP</ref>