Portulaca is a genus of flowering plants in the family Portulacaceae, and is the type genus of the family. With over 100 species, it is found in the tropics and warm temperate regions. Portulacas are also known as the purslanes.

The Portulacaceae are a family of flowering plants, comprising 115 species in a single genus Portulaca. Formerly some 20 genera with about 500 species, were placed there, but it is now restricted to encompass only one genus, the other genera being placed elsewhere. The family has been recognised by most taxonomists, and is also known as the purslane family. It has a cosmopolitan distribution, with the highest diversity in semiarid regions of the Southern Hemisphere in Africa, Australia, and South America, but with a few species also extending north into Arctic regions. The family is very similar to the Caryophyllaceae, differing in the calyx, which has only two sepals.