9. Alternanthera Forsskål, Fl. Aegypt.-Arab. 28. 1775.
[Latin alternans, alternating, and anthera, anther, referring to the alternation of pseudostaminodes and stamens]
Steven E. Clemants
Herbs or subshrubs, annual or perennial. Stems prostrate, decumbent, ascending, erect, or floating, indumentum of simple trichomes. Leaves opposite, sessile or petiolate; blade lanceolate to ovate, ovate-rhombic, or obovate-rhombic, margins entire. Inflorescences axillary or terminal, sessile or pedunculate, several-flowered cylindric spikes or globose heads, without immediately subtending leaves; bracts and bracteoles scarious. Flowers bisexual; tepals 5, distinct; stamens 3-5; filaments connate basally into tube or short cup; pseudostaminodes 5, alternating with stamens; ovule 1; style 1, ca. 0.2 mm; stigma capitate or rarely 2-lobed. Utricles compressed, ovoid or obovoid, indehiscence. Seeds 1, reddish brown, lenticular or ovoid-oblong.
Species ca. 80 (9 in the flora): primarily American tropics and subtropics, some in Asia, Africa, and Australia.
SELECTED REFERENCE
Mears, J. A. 1978. The nomenclature and type collections of the widespread taxa of Alternanthera (Amaranthaceae). Proc. Acad. Nat. Sci. Philadelphia 129: 1-21.
