Eriocaulon is a genus of about 400 species of monocotyledonous flowering plants in the family Eriocaulaceae, commonly known as pipeworts.

The genus is widely distributed, with the centers of diversity for the group occurring in tropical regions, particularly southern Asia and the Americas.

Only one species (E. aquaticum) occurs in Europe, where it is confined to the Atlantic Ocean coasts of Scotland and Ireland;[4] this species also occurs in eastern North America and is thought to be a relatively recent natural colonist in Europe.

In wet soils, their abundance appears to be related to water levels, fire frequency, and competition from other plants such as grasses.

Experiments have shown that they are weak competitors compared to many other wetland plant species.