Callitriche is a genus of largely aquatic plants known as water-starwort. Previously, it was the only genus in the family Callitrichaceae. However, according to the APG II system this family is now included in the Plantaginaceae (plantain family). The family name Callitrichaceae retains its status as nomen conservandum (name to be retained).

Species: 75 species are accepted.

• Callitriche alata
• Callitriche albomarginata
• Callitriche anisoptera
• Callitriche antarctica – Antarctic water-starwort
• Callitriche aucklandica
• Callitriche berteroana
• Callitriche brachycarpa
• Callitriche brevistyla
• Callitriche brutia – pedunculate water starwort
• Callitriche capricorni
• Callitriche chathamensis
• Callitriche christensenii
• Callitriche ciliata
• Callitriche compressa
• Callitriche concinna
• Callitriche cophocarpa
• Callitriche cribrosa
• Callitriche cyclocarpa
• Callitriche cycloptera
• Callitriche dacryoidea
• Callitriche deflexa
• Callitriche ecarinata
• Callitriche fassetti – Fassett´s water starwort
• Callitriche favargera
• Callitriche fehmedianii
• Callitriche fuliginea
• Callitriche fuscicarpa
• Callitriche glareosa
• Callitriche hamulata – intermediate water starwort
• Callitriche hedbergiorum
• Callitriche hegelmaieriana
• Callitriche hermaphroditica (synonym C. autumnalis ) – autumn water starwort
• Callitriche heterophylla (synonyms C. anceps and C. bollanderi ) – differentleaf water starwort
• Callitriche insularis
• Callitriche japonica (synonym C. nana )
• Callitriche keniensis
• Callitriche lechleri
• Callitriche lenisulca
• Callitriche longipedunculata – longstalk water starwort
• Callitriche lusitanica
• Callitriche mandonis
• Callitriche marginata (synonym C. sepulta ) – winged water starwort
• Callitriche mathezii
• Callitriche mouterdei
• Callitriche muelleri
• Callitriche nubigena
• Callitriche × nyrensis
• Callitriche oblongicarpa
• Callitriche obtusangula – blunt-fruited water starwort
• Callitriche occidentalis
• Callitriche oreophila
• Callitriche palustris – spiny water starwort
• Callitriche papuana
• Callitriche pedunculosa (synonym C. nuttallii ) – Nuttall´s water starwort
• Callitriche peploides – matted water starwort
• Callitriche petrieri
• Callitriche platycarpa – various-leaved water starwort
• Callitriche praetermissa
• Callitriche pulchra – beautiful water starwort
• Callitriche quindiensis
• Callitriche raveniana
• Callitriche regis-jubae
• Callitriche rimosa
• Callitriche schotsmaniana
• Callitriche sonderi
• Callitriche stagnalis – pond water starwort
• Callitriche terrestris (synonym C. austinii ) – terrestrial water starwort
• Callitriche transvolgensis
• Callitriche trochlearis – effluent water starwort
• Callitriche truncata – short-leaved water starwort
• Callitriche turfosa
• Callitriche umbonata
• Callitriche × vigens
• Callitriche vulcanicola
• Callitriche wightiana

Phylogeny and evolution: The first molecular phylogeny of the aquatic genus of 50 species discerned three clades: Clade A (three species, widespread); Clade C (10 species, New World); Clade D (six species, Europe). The parsimony analyses revealed that aneuploid reduction (n=5 to 4) and polyploidy (n=5 to 10) have evolved at least twice in the genus, whereas the obligately submersed growth habit and hypohydrophily have evolved once.