A new addition to the alien flora of Tunisia, Amaranthus spinosus L. (Amaranthaceae s.l.), with notes on A. diacanthus Raf.

Abstract Amaranthus spinosus L. (Amaranthaceae s.l.), a species native to the Neotropics, has been found in four localities (Bizerta, Bir Bouregba, Hammamet, and Nabeul) of N. Tunisia. Our discovery represents the first record at national level, and the second one for N. Africa. Morphological characters and ecological data are given. Nomenclatural notes are provided for the name A. diacanthus, which was regarded by some authors as heterotypic synonym of A. spinosus. A neotype is designated in the present paper based on a specimen preserved at LSU