Revisión Taxonómica de las Especies Monoicas de Amaranthus (Amaranthaceae): Amaranthus subg. Amaranthus y Amaranthus subg. Albersia
The genus Amaranthus L. (Amaranthaceae) is characterized by its monoecious or dioecious herbs, with alternate leaves, unisexual flowers protected by bracts and bracteoles, usually three to five glabrous sepals, free stamens, and fruit a utricle or pyxidium. A taxonomic revision of the monoecious species of Amaranthus is presented for those species that comprise Amaranthus subg. Amaranthus (13 species) and Amaranthus subg. Albersia (Kunth) Gren. & Godr. (52 species). Forty-six of these 65 species are American, while the rest (19) are from Africa, Australia, and Eurasia. The following taxa are newly synonymized: A. artineanus Muschl. with A. hybridus L. subsp. quitensis (Kunth) Costea & Carretero and A. chihuahuensis S. Watson with A. torreyi (A. Gray) S. Watson. Names at new rank (varieties elevated to subspecies) are proposed for A. asplundii Thell. subsp. australis (Hunz.) N. Bayón, A. blitum L. subsp. pseudogracilis (Thell.) N. Bayón, A. crassipes Schltdl. subsp. warnockii (I. M. Johnst.) N. Bayón, and A. macrocarpus Benth. subsp. pallidus (Benth.) N. Bayón. Fifteen lectotypes are newly designated for Amarantellus argentines Speg., Amaranthus albomarginatus Uline & W. L. Bray, A. asplundii Thell., A. ataco Thell., A. bigelovii Uline & W. L. Bray, A. blitum L. subsp. emarginatus (Uline & W. L. Bray) Carretero, Muñoz Garmendia & Pedrol, A. bracteosus Uline & W. L. Bray, A. caudatus L. var. alopecurus Moq., A. graecizans L. subsp. aschersonianus (Thell.) Costea, D. M. Brenner & Tardif, A. schinzianus Thell., A. sclerantoides (Andersson) Andersson, A. squamulatus (Andersson) B. L. Rob., A. wrightii S. Watson, Amblogyna squarrulosa A. Gray, and Sarratia Moq. A neotype is designated for A. vulgatissimus Speg. and an epitype is designated for A. ascendens Loisel. Complete illustrations are offered for 14 species never illustrated before, and for another eight species that were only partially illustrated in the past.