An annual, biennial, or perennial herbaceous plant (family Papaveraceae), most species having large, colourful, often solitary flowers that may be of many colours. The fruit is a capsule and most species exude a latex when wounded. The field or corn poppy (Papaver rhoeas), with bright red flowers, is a weed of arable fields that flowered on the battlefields of World War I, and is used to commemorate those who died in war. P. somniferum, with white, red, or mauve flowers, is the opium poppy. Eschscholzia californica is Californian poppy. There are 44 genera with 760 species occurring worldwide in temperate regions.