Herbs or subshrubs, shrubs, or small trees , annual, biennial, or perennial, scapose or caulescent, usually from taproots, sometimes from rhizomes; sap clear, white, or colored, often sticky. Stems leafy or naked, erect, spreading, or decumbent, simple or branching. Leaves basal and/or cauline, alternate to opposite or whorled, simple, without stipules, petiolate or sessile; blade unlobed or with 1-3 odd-pinnate, subpalmate, or palmate orders of lobes. Inflorescences axillary or terminal, unifloral or else multifloral and cymiform, racemose, umbelliform, corybiform, or paniculate, pedunculate or subsessile; bracts usually present. Flowers radially symmetric, pedicellate or sessile; receptacle sometimes expanded and forming cup or ring beneath calyx (only in Eschscholzia , Meconella , and Platystemon ); perianth and androecium sometimes perigynous; sepals caducous, 2 or 3, distinct or connate, usually obovate; petals distinct, usually obovate, mostly 2 times number of sepals, sometimes more or absent; stamens many or 4-15 (only in Meconella and Canbya ); anthers 2-locular; pistil 1, 2-18[-22]-carpellate; ovary 1-2-locular or incompletely to completely multilocular by placental intrusion; placentas 2 or more, parietal; style 1 or absent; stigmas or stigma lobes 2-many. Fruits capsular, dehiscence valvate, poricidal, or transverse, or carpels dissociating and breaking transversely into 1-seeded segments (only in Platystemon ). Seeds usually many, small, sometimes arillate or carunculate.

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• 4
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Herbs, annual, biennial, monocarpic perennial, perennial, or shrubby. Laticifers or elongated idioblasts present. Leaves alternate or in a basal rosette, rarely opposite or whorled, usually without stipules; leaf blade entire to compound. Inflorescences racemes, panicles, dichasia, pseudoumbels, or solitary flowers. Flowers actinomorphic, bisymmetric, or zygomorphic, always bisexual, usually 2-merous, rarely 3- or 4-merous. Calyx caducous, green or petaloid. Corolla choripetalous or quasi-sympetalous, very rarely absent. Anthers opening by slits. Ovary superior, syncarpous with 2 to several carpels; placentation parietal.

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• 5
]. 

Annual, biennial, or perennial herbs with coloured juice, often glaucescent and prickly, or rarely shrubs or small trees; root usually a rhizome or tuber

Source: [
• 1
]. 

Sepals 2, rarely 3, green, falling off separately on the opening of the flower or united into a deciduous calyptra

Source: [
• 1
]. 

Perianth of calyx and corolla, or rarely the latter absent

Source: [
• 1
]. 

Flowers hermaphrodite, actinomorphic, hypogynous or rarely perigynous, mostly solitary, fugacious and visited by pollen-eating insects

Source: [
• 1
]. 

Leaves exstipulate, alternate, rarely the floral leaves opposite or whorled, much divided, rarely entire

Source: [
• 1
]. 

Petals showy, 4 or 6, rarely 8 or 12, free, imbricate and often crumpled in the bud, deciduous

Source: [
• 1
]. 

Stamens numerous, rarely few, free, with filiform filaments; anthers mostly nearly as long as the filaments, 2-celled, dehiscing by longitudinal slits

Source: [
• 1
]. 

Fruit a capsule, opening by valves or pores

Source: [
• 1
]. 

Ovules numerous, rarely solitary

Source: [
• 1
]. 

Seeds small, with minute embryo in fleshy or oily endosperm

Source: [
• 1
]. 

Ovary free, of 2 or more united carpels, 1-celled with parietal placentas, or several-celled by the placentas reaching to the middle

Source: [
• 1
]. 

Seeds small, numerous; endosperm oily

Source: [
• 2
]. 

Ovary syncarpous, 1-locular with parietal placentas (rarely multilocular or spuriously 2-locular) and numerous ovules

Source: [
• 2
]. 

Fruit usually a capsule dehiscing by valves or pores

Source: [
• 2
]. 

Petals 4–6 (12) free, imbricate, fugacious

Source: [
• 2
]. 

Stamens usually numerous

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• 2
]. 

Flowers actinomorphic, bisexual, usually hypogynous

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• 2
]. 

Sepals 2–3, imbricate, free or calyptrate, caducous

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• 2
]. 

Annual, biennial or perennial herbs (rarely shrubby), usually with white or yellowish latex, with alternate, exstipulate leaves

Source: [
• 2
]. 

Annual, biennial or perennial herbs, rarely shrubs, and only 1 tree genus (Bocconia L.), with white, yellow or orange coloured latex

Source: [
• 3
]. 

Flowers usually solitary, conspicuous and large, bisexual, regular, hypogynous

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• 3
]. 

Sepals 2–3, imbricate, usually free or calyptrate, caducous

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• 3
]. 

Leaves alternate or rarely whorled, exstipulate, entire to much divided (palmately, pinnately etc.)

Source: [
• 3
]. 

Ovary superior, usually unilocular, more rarely with 2 to several locules ; ovules numerous ; placentation parietal

Source: [
• 3
]. 

Stigmas opposite or alternate with placentas

Source: [
• 3
]. 

Petals (4–)6(–12), more rarely absent, imbricate, arranged in l–2(–3) whorls, crumpled in bud

Source: [
• 3
]. 

Stamens free, usually numerous, spirally arranged, rarely 4 and cyclic ; anthers 2-celled with longitudinal dehiscence

Source: [
• 3
]. 

Seeds small, numerous, with minute embryo and copious, usually oily, endosperm

Source: [
• 3
]. 

Fruit usually a capsule dehiscing by valves or pores, rarely indehiscent

Source: [
• 3
]. 

SELECTED REFERENCES

Ernst, W. R. 1962. A Comparative Morphology of the Papaveraceae. Ph.D. dissertation. Stanford University. Ernst, W. R. 1962b. The genera of Papaveraceae and Fumariaceae in the southeastern United States. J. Arnold Arbor. 43: 315-343. Ernst, W. R. 1967. Floral morphology and systematics of Platystemon and its allies Hesperomecon and Meconella (Papaveraceae: Platystemonoideae). Univ. Kansas Sci. Bull. 47: 25-70. Fedde, F. 1909. Papaveraceae-Hypecoideae et Papaveraceae-Papaveroideae. In: H. G. A. Engler, ed. 1900-1953. Das Pflanzenreich. 107 vols. Berlin. Vol. 40[IV,104], pp. 1-430. Fedde, F. 1936. Papaveraceae. In: H. G. A. Engler et al., eds. 1924+. Die natürlichen Pflanzenfamilien, ed. 2. 26+ vols. Leipzig and Berlin. Vol. 17b, pp. 5-145. Grey-Wilson, C. 1993. Poppies: A Guide to the Poppy Family in the Wild and in Cultivation. Portland. Gunn, C. R. 1980. Seeds and fruits of Papaveraceae and Fumariaceae. Seed Sci. Techn. 8: 3-58. Gunn, C. R. and M. J. Seldin. 1976. Seeds and Fruits of North American Papaveraceae. Washington. [U.S.D.A. Agric. Res. Serv., Techn. Bull. 1517.] Harms, H. 1936. Reihe Rhoeadales. In: H. G. A. Engler et al., eds. 1924+. Die natürlichen Pflanzenfamilien, ed. 2. 26+ vols. Leipzig and Berlin. Vol. 17b, pp. 1-4. Hutchinson, J. 1925. Contributions towards a phylogenetic classification of flowering plants: V. The genera of Papaveraceae. Bull. Misinform. Kew 1925: 161-168. Kadereit, J. W. 1993. Papaveraceae. In: K. Kubitzki et al., eds. 1990+. The Families and Genera of Vascular Plants. 2+ vols. Berlin etc. Vol. 2, pp. 494-506. Stermitz, F. R. 1968. Alkaloid chemistry and the systematics of Papaver and Argemone. Recent Advances Phytochem. 1: 161-183.

Source: [
• 4
].