ABSTRACT
Amaranthus is a genus of tropical origin that belongs to the Amaranthaceae. Today it is widely distributed all over the world, with species reaching temperate regions even before man converted some of them into cosmopolitan weeds or domesticates (crops or ornamentals). 15 About 60 species are native to the Americas, and about 15 others to Europe, Asia, Africa, and Australia. Most of them are pioneer annuals of naturally open habitats, producing abundant seed. They thrive by constant colonization of sites of disturbed soil, with full sun and little competition. Long natural selection for such a way of life preadaptated certain of the species for success in habitats drastically disturbed by man. Thus, today Amaranthus spp. are best known as noxious weeds (e.g., A. hybridus L., A. retroflexus L., A. spinosus L.,A. powellii S. Wats.). However, in tropical and subtropical countries, certain species are grown for grain (A. hypocondriacus L., A. cruentus L., A. caudatus L.), whereas the young plants of others are eaten as pot-herbs (A. dubius Mart., A. tricolor L.). Other species are cultivated as ornamentals for their highly colored inflorescence (A. caudatus L.) or leaves (A. tricolor L.).
