Amaranthus spinosus

Raus, Thomas, 2022, Taxonomic, nomenclatural and floristic review of Amaranthaceae of Greece and neighbouring countries, Willdenowia 52 (3), pp. 335-357 : 347

21. Amaranthus spinosus L., Sp. Pl.: 991. 1753. – Lectotype (designated by Fawcett & Rendle 1914: 130): Herb. Linn. No. 1117.27 ( LINN).

Remarks — Native to the lowlands of tropical America, from NE Mexico to N Argentina, Amaranthus spinosus spread as a pantropical weed and is now introduced to warm-temperate regions of North America, Europe (scattered), Africa, E Asia and Australia ( Bayón 2015: 295; POWO 2022). It is a valued food plant in Africa and Asia (from India to the Philippines) and can be a noxious weed in rice cultivation. It is a rare casual alien in Greece, not naturalized ( Arianoutsou & al. 2010), easily recognized by its paired internodal spines and so far reported from the Nomoi of Attiki, Lakonia, Pieria and Thessaloniki. It is also known to occur in Albania, North Macedonia, Bulgaria and Turkey ( Iamonico 2015a). According to Song & al. (2000), this taxonomically isolated species, the sole member of A. sect. Centrusa Griseb., occupies an evolutionarily basal position for the clades of A. subg. Amaranthus (A. sect. Amaranthus ) and A. subg. Albersia (Kunth) Gren. & Godr. (A. sect. Blitopsis Dumort.); it also shows some degree of morphological transition toward dioecious amaranths of A. subg. Acnida , either indicating a phylogenetic relationship or a parallel evolution ( Mosyakin & Robertson 1996).