THE NOMENCLATURE AND TYPE COLLECTIONS OF THE WIDESPREAD TAXA OF ALTERNANTHERA (AMARANTHACEAE)

Abstract

The nomenclature and type collections of the widespread and reputedly widespread taxa of Alternanthera Forsskal are discussed in detail. The nine widespread taxa are Alternanthera sessilis (L.) DC., A. paronychioides St.-Hilaire, A. brasiliana var. villosa (Moq.) Kuntze, A. philoxeroides (Mart.) Gris., A. pungens HBK., A. caracasana HBK., A. maritima (Mart.) St.-Hilaire, A. tenella Colla and A. bettzichiana (Regel) Voss. The taxa erroneously reported to be widespread are Alternanzthera brasiliana (L.) Kuntze, A. truxillensis HBK. and A. echinocephala (Hook.f.) Christopherson. Two new combinations are included: Alternanthera maritima var. sparmannii (Moq.) Mears and Alternanthera philoxeroides forma phyllantha (Seubert) Mears. A key to the widespread taxa is provided. Alternanthera Forsskal is a genus of ap- proximately 80 species, most endemic to South America. A study of about 10,000 specimens from A, BM, BR, CAS, F, G, GH, K, LIL, LINN, M, NA, NY, P, PENN, PH and S has led to a preliminary revision. Since the publication of that revision must await several field projects with problem groups, as well as the production of illus- trations, the nomenclature of the widespread species of Alternanthera is published here. The nomenclature of the widespread spe- cies in various floras accounts for the great majority of errors and confusion regarding Alternanthera.