AMARANTHL75 ACANTHOBRACTEATUS (AMARANTHACEAE)

摘要

Amaranthus acanthobracteatus is described as a new species from the sand dunes at Bilbao near Viesca in southern Coahuila, Mexico. It is a sister species to the dioecious A. acanthochiton, that has been recognized as a distinct genus Acanthochiton. Both species are psammophytic, dioecious annuals with large chartaceous, sharp-pointed pistillate bracts. The new taxon differs from A. acanthochiton in its longer, less cordate, distally recurved pistillate bracts, its larger seeds, larger pistillate inflorescences, and in many minor characteristics. The new species also is larger, with pistillate plants maturing as tumbleweeds.