The bracteoles and perigone are persistent in the fruits and are structurally different in both species.
Vanessa de Carvalho Harthman, Luiz Antonio de Souza 2012, 'Ontogenia do fruto em desenvolvimento de Alternanthera tenella Colla e Amaranthusblitum Linnaeus (Amaranthaceae) Ontogeny of fruits of Alternanthera tenella Collaand Amaranthus blitum Linnaeus (Amaranthaceae)', Acta Botânica Brasílicahttp://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062012000300013. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)