Amaranth

Amaranthus, collectively known as amaranth, is a cosmopolitan genus of annual or short-lived perennial plants. Some amaranth species are cultivated as leaf vegetables, pseudocereals, and ornamental plants. Most of the Amaranthus species are summer annual weeds and are commonly referred to as pigweed. Catkin-like cymes of densely packed flowers grow in summer or autumn. Approximately 60 species are recognized, with inflorescences and foliage ranging from purple, through red and green to gold. Members of this genus share many characteristics and uses with members of the closely related genus Celosia. 'Amaranth' derives from Greek ἀμάραντος (amárantos), 'unfading', with the Greek word for 'flower', ἄνθος (ánthos), factoring into the word's development as amaranth. Amarant is an archaic variant. Amaranthus shows a wide variety of morphological diversity among and even within certain species. Although the family (Amaranthaceae) is distinctive, the genus has few distinguishing characters among the 70 species included. This complicates taxonomy and Amaranthus has generally been considered among systematists as a 'difficult' genus. Formerly, Sauer (1955) classified the genus into two subgenera, differentiating only between monoecious and dioecious species: Acnida (L.) Aellen ex K.R. Robertson and Amaranthus. Although this classification was widely accepted, further infrageneric classification was (and still is) needed to differentiate this widely diverse group. Currently, Amaranthus includes three recognized subgenera and 70 species, although species numbers are questionable due to hybridization and species concepts. Infrageneric classification focuses on inflorescence, flower characters and whether a species is monoecious/dioecious, as in the Sauer (1955) suggested classification. A modified infrageneric classification of Amaranthus was published by Mosyakin & Robertson (1996) and includes three subgenera: Acnida, Amaranthus, and Albersia. The taxonomy is further differentiated by sections within each of the subgenera. Species include: Uncooked amaranth grain is 12% water, 65% carbohydrates (including 7% dietary fiber), 14% protein, and 7% fat (table). A 100 grams (3.5 oz) reference amount of uncooked amaranth grain provides 371 calories, and is a rich source (20% or more of the Daily Value, DV) of protein, dietary fiber, pantothenic acid, vitamin B6, folate, and several dietary minerals (table). Uncooked amaranth is particularly rich in manganese (159% DV), phosphorus (80% DV), magnesium (70% DV), iron (59% DV), and selenium (34% DV). Cooking decreases its nutritional value substantially across all nutrients, with only dietary minerals remaining at moderate levels.