Amaranthus tricolor is an ornamental plant known as Tandaljo or Tandalja bhaji in India,callaloo in the Caribbean and Joseph's coat after the Biblical figure Joseph, who is said to have worn a coat of many colors. Although it is native to South America, many varieties of amaranth can be found across the world in a myriad of different climates due to it being a C4 carbon fixation plant, which allows it to convert carbon dioxide into biomass at an extremely efficient rate when compared to other plants. Cultivars have striking yellow, red and green foliage.
The leaves may be eaten as a salad vegetable as well as the stems. In Africa, it is usually cooked as a leafy vegetable. It is usually steamed as a side dish in both China and Japan.
Amaranthus gangeticus is considered a synonym of A. tricolor, but has been recognized as a separate species in the past. Amaranthus gangeticus is also known as elephant-head amaranth. It is an annual flowering plant with deep purple flowers. It can grow from 2–3 feet in height. In Bangladesh, it has been used as a leafy vegetable. Scientific study suggests that it may inhibit calcium retention.
^Larsen, T.; Thilsted, S. H.; Biswas, S. K.; Tetens, I. (2007). "The leafy vegetable amaranth (Amaranthus gangeticus) is a potent inhibitor of calcium availability and retention in rice-based diets". British Journal of Nutrition90 (3): 521–527. doi:10.1079/BJN2003923. PMID13129457.edit