seven; see text Guilleminea is a small genus of plants in the family Amaranthaceae.

These are prostrate, mat-forming perennial herbs growing from taproots.

The genus includes seven species native to the Americas, ranging from Arkansas, Colorado, and California to northern Argentina.

[1] The best known species is perhaps Guilleminea densa, the small matweed, which has been introduced to parts of Africa, Australia, and the eastern United States where it is a weed.

The genus was named after the French botanist Jean Baptiste Antoine Guillemin.