Alternanthera is a genus of flowering plants in the family Amaranthaceae. It is a widespread genus with most species occurring in the tropical Americas, and others in Asia, Africa, and Australia. Several species are notorious noxious weeds.
Description
These are annual or perennial herbs or subshrubs. While some of the better-known species are aquatic plants, most are terrestrial.
Species
thumb|right|250px|Alternanthera 'Party Time'
thumb|right|250px|[[Alternanthera sessilis]]
thumb|right|250px|[[Alternanthera polygonoides]]
It is not yet clear how many species belong in the genus. Estimates range between 80 and 200. Plants of the World Online accepts 106 species. sea-urchin joyweed
- Alternanthera fasciculata
- Alternanthera fastigiata
- Alternanthera ficoidea – parrot leaf
- Alternanthera filifolia <small>(Hook.f.) J.T.Howell</small>
- Alternanthera flava
- Alternanthera flavescens – yellow joyweed
- Alternanthera flavicoma
- Alternanthera flavida
- Alternanthera flosculosa
- Alternanthera galapagensis
- Alternanthera geniculata
- Alternanthera glaziovii
- Alternanthera grandis
- Alternanthera halimifolia – West Indian joyweed
- Alternanthera helleri <small>(B.L.Rob.) J.T.Howell</small>
- Alternanthera herniarioides
- Alternanthera hirtula
- Alternanthera inaccessa
- Alternanthera indica
- Alternanthera ingramiana
- Alternanthera jacquinii
- Alternanthera januarensis
- Alternanthera kanhae
- Alternanthera kurtzii
- Alternanthera laguroides
- Alternanthera lanceolata
- Alternanthera laxa
- Alternanthera littoralis <small>P.Beauv.</small> – seaside joyweed
- Alternanthera lupulina
- Alternanthera macbridei
- Alternanthera martii
- Alternanthera micrantha
- Alternanthera microphylla
- Alternanthera minutiflora
- Alternanthera mollendoana
- Alternanthera multicaulis
- Alternanthera nahui
- Alternanthera nesiotes
- Alternanthera nodiflora – common joyweed
- Alternanthera obovata
- Alternanthera olivacea
- Alternanthera panamensis
- Alternanthera paronichyoides <small>A.St.-Hil.</small> – smooth joyweed
- Alternanthera pennelliana
- Alternanthera peruviana
- Alternanthera philippo-coburgii
- Alternanthera philoxeroides <small>(Mart.) Griseb.</small> – alligator weed
- Alternanthera porrigens
- Alternanthera praelonga
- Alternanthera puberula
- Alternanthera pubiflora
- Alternanthera pulchella
- Alternanthera pulverulenta
- Alternanthera pumila
- Alternanthera pungens
- Alternanthera pycnantha
- Alternanthera raimondii
- Alternanthera regelii
- Alternanthera reineckii <small>Briq.</small>
- Alternanthera robinsonii
- Alternanthera rufa
- Alternanthera rugulosa
- Alternanthera serpens
- Alternanthera serpyllifolia
- Alternanthera sessilis <small>(L.) DC.</small> – rabbit-meat, sessile joyweed, downy joyweed, hairy joyweed
- Alternanthera snodgrassii
- Alternanthera spinosa
- Alternanthera stellata
- Alternanthera stenophylla
- Alternanthera suessenguthii
- Alternanthera tetramera
- Alternanthera tomentosa
- Alternanthera tubulosa
- Alternanthera vestita
- Alternanthera villosa
Formerly placed here
- Gomphrena subscaposa (as Alternanthera subscaposa )
Ecology
Many species have been reported as noxious weeds, including A. angustifolia, A. caracasana, A. denticulata, A. nana, A. nodiflora, A. paronychioides, A. philoxeroides, A. sessilis, A. tenella, and A. triandra.