Amaranthaceae

Abstract

Amaranthaceae, known as the amaranth family, in the order of Caryophyllales, is a family of flowering plants, including the former goosefoot family Chenopodiaceae according to gene-based APG system and the APG II system, showing paraphyletic, containing of about 165 genera with approximately 2040 species so far, making the family the most species-rich lineage within the flowering plants in Caryophyllales. Plants are usually annual or perennial herbs or subshrubs or shrubs, rarely vines or trees, and occasionally succulent. Stems are often with thickened node. Leaves are often alternate, sometimes opposite, exstipulate, often flat or terete, with variable shapes, and with margins entire or toothed. Flowers are often bisexual, occasionally unisexual, actinomorphic, solitary or aggregated to cymose, and spicate or paniculate. Bracts and bracteoles are herbaceous and scarious. Tepals are often 5, rarely 8, and joined. Stamens are 1–5, opposite to tepals or alternating, inserting from a hypogynous disk, often with appendages. Anthers are with two or four pollen sacs. Carpels are 1–3, rarely 6. Ovary is superior. Ovules are 1 and rarely 2. Fruit is a utricle, rarely a capsule or berry, with persistent perianth. Seeds are with thickened or woody seed coat. Embryo is exalbuminous. Eighteen species, belonging to six different genera, are illustrated in this chapter.