Habit: [Annual] perennial herb, aquatic to terrestrial.
Stem: prostrate or ascending; hairs simple.
Leaf: opposite, subsessile to short-petioled, blade margins entire to serrate.
Inflorescence: axillary or axillary and terminal, sessile or peduncled, many-flowered cylindric spikes or spheric heads; bracts and bractlets persistent, scarious.
Flower: bisexual; perianth parts 5, free, +- equal or not, scarious, persistent, white, glabrous or woolly; stamens 3--5, fused at base into short tube or cup, anthers 2-chambered; pseudostaminodes 5, alternate with stamens; ovary obovoid to +- spheric; style short, +- 0.2 mm; stigma spheric (2-lobed), ovule 1, pendent.
Fruit: indehiscent; fruit wall membranous.
Seed: 1, lenticular or ovoid-oblong, +- red brown, smooth, shiny.
Species In Genus: +- 170 species: generally tropical America.
Etymology: (Latin: alternating pseudostaminodes and stamens)
Note: Alternanthera sessilis (L.) DC. occasionally a greenhouse weed
; Alternanthera ficoidea (L.) P. Beauv. var. bettzickiana (Regel) Backer widely cultivated, California reports unconfirmed.
Jepson eFlora Author: Mihai Costea
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)
Key to Alternanthera
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