The canna's showy 'petals' are really transformed stamens
Canna lilies are not lilies at all but cousins of gingers and bananas. Their blazing red and orange blooms are mostly modified stamens, while the true petals hide underneath. Below ground, the swollen rhizomes hold the largest starch grains known in any plant, which is why cannas have been food for thousands of years.
Canna is the sole genus in its family, Cannaceae, with 10 species native to the American tropics and subtropics, from the southern United States down to northern Argentina. Botanists once recognised 50 to 100 species until Paul Maas in the Netherlands and Nobuyuki Tanaka in Japan folded most into synonyms late in the 20th century. The name comes from the Latin for cane or reed. Classification places cannas in the order Zingiberales alongside gingers, arrowroots, heliconias and birds of paradise.
The flower is a small deception. Three sepals and three petals are small and tucked beneath flamboyant staminodes, sterile stamens that look like petals. One fertile stamen carries pollen on half an anther. In wild species and early hybrids the anther sits high, so pollen lands on the stigma and the plant fertilises itself; later cultivars rely on bees, hummingbirds, sunbirds or bats landing on the lip-like labellum. Cannas are also the only monocots known to have dormant seeds, thanks to an extremely hard seed coat.
Canna indica, called achira in Latin America, was among the earliest plants domesticated in the Americas, grown by Native Americans for millennia for its edible root. Its species name misleads: Charles de l'Ecluse, who first described it, explained it was called indica because it came from the West Indies, not India. Today every part is useful. Rhizomes give starch, stems and leaves feed livestock, young shoots are eaten as a vegetable, and in Vietnam the starch makes cellophane noodles called miến dong. Stem fibre substitutes for jute, and leaf fibre makes a tan paper.
Victorian gardeners across Europe, India and the United States made cannas a sensation, and a large horticultural trade still depends on them. They grow even in Arctic-Circle countries if given 6 to 8 hours of sun daily and shelter from winter frost. Their seeds rattle inside the kayamb of Réunion and Zimbabwe's hosho, and in Thailand cannas are a traditional Father's Day gift.
Source: Canna (plant)
