Nyctaginaceae, the four o'clock family, is a family of around 33 genera and 290 species of flowering plants, widely distributed in tropical and subtropical regions, with a few representatives in temperate regions. The family has a unique fruit type, called an "anthocarp", and many genera have extremely large (>100 µm) pollen grains. The family has been almost universally recognized by plant taxonomists. The APG II system (2003; unchanged from the APG system of 1998), assigns it to the order Caryophyllales in the clade core eudicots.