Revisión Taxonómica de las Especies de Alternanthera (Amaranthaceae) del Cono Sur (Argentina, Sur de Brasil, Chile, Paraguay y Uruguay) y Bolivia
The genus Alternanthera Forssk. (Amaranthaceae) is widely distributed throughout tropical and subtropical areas of the Americas. It includes herbs or suffrutices with opposite leaves, perfect flowers protected by a bract and two bracteoles, with capitate stigma and appendages in the staminal tube (or pseudostaminodes) arranged alternately with the stamen filaments, which bear functionally unilocular anthers. Here, a taxonomic revision of the 31 species of Alternanthera that inhabit the Southern Cone and Bolivia is presented. The name A. piptantha Pedersen is synonymized with A. altacruzensis Suess. Type species are designated for genera Brandesia Mart., Bucholzia Mart., Mogiphanes Mart., Steiremis Raf., and Telanthera R. Br. In addition, lectotypes are designated for Achyranthes porrigens Jacq., Alternanthera mexicana (Schltdl.) Hieron. var. gracilis Suess., A. nodiflora R. Br. var. linearifolia Moq., A. tenella Moq., Gomphrena elongata Willd. ex Roem. & Schult., T. meyeriana Regel & Körn, T. rufa (Mart.) Moq. var. glabrata Seub., and a second-step lectotype for A. denticulata R. Br. Identification keys are included for the differentiation of species, subspecies, and varieties, as well as their morphological descriptions, geographic distribution, habitat, vernacular names, uses, illustrations, nomenclatural notes, and information about the studied specimens.