Perfect, actinomorphic (zygomorphic in Fumarioideae); perianth parts free; sepals cauducous; carpels syncarpous; ovary superior, usually 1-locular with many parietal ovules; stamens numerous (or only 6 in Fumarioideae) petals sometimes crumpled in bud.

Inflorescences:

Flowers solitary or cymes and racemes

Fruits:

Capsules (poricidal in Papaver); seeds often with fleshy arils forming elaiosomes for ant dispersal

Habit:

Annual or perennial herbs, rarely woody; sap milky or colored, often bright orange, red, or yellow (clear in Fumarioideae), some with alkaloids

Leaves:

Alternate to opposite or whorled, entire to lobed or dissected

Examples:

Sanguinaria canadensis — bloodroot
Papaver orientale — Oriental poppy
Papaver somiferum — opium poppy
Stylophorum diphyllum — Celandine poppy
Chelidonium majus — Celandine
Meconopsis grandis — blue poppy
Escholtzia californica — California poppy
Argenome mexicana — prickly poppy
Macleaya microcarpa — plume poppy
Bocconia frutescens — tree poppy

Fumarioideae:

Dicentra spectabilis — bleeding-heart
Dicentra cucullaria — Dutchman's breeches
Dicentra canadensis — squirrel-corn
Corydalis species — corydalis, fumewort