Alternanthera angustifolia

{{Short description|Species of flowering plant}}

{{use dmy dates|date=November 2021}}

{{Speciesbox

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| taxon = Alternanthera angustifolia

| | authority = R.Br.

| synonyms_ref = {{APNI2|id=84083|name= Alternanthera angustifolia}}

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| range_map_caption = Occurrence data from AVH

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Alternanthera angustifolia (narrow-leaf joyweed){{Cite web|last=Australia|first=Atlas of Living|title=Species: Alternanthera angustifolia (Narrow-Leaf Joyweed)|url=https://bie.ala.org.au/species/https://id.biodiversity.org.au/taxon/apni/51266475|access-date=2021-11-06|website=bie.ala.org.au|language=en-AU}} is a small herb in family Amaranthaceae{{FloraBase|id=2647|name=Alternanthera angustifolia}} found widely in inland Australia from northern Western Australia, the Northern Territory, South Australia, New South Wales to Queensland.

It is a prostrate (or decumbent) annual herb, growing from 2 cm to 30 cm high, on sandy soils on creek and river banks. Its small{{Cite Q|Q106088428|pages=91}} white flowers may be seen from April to August.

Alternanthera angustifolia was first described in 1810 by Robert Brown.{{cite Q|Q7247677|pages= 417|url=https://www.biodiversitylibrary.org/page/36315694}}