Robert W. Kiger

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.

Genera 25-30 (17 genera, 63 species in the flora): worldwide, mainly Northern Hemisphere.

According to W. R. Ernst (1962b), Papaveraceae "may be divided conveniently into four subfamilies." His scheme is followed here, but with the subfamilies taken up in alphabetic order; they seem to be natural groups, but their phylogenetic interrelationships are not yet clear. Similarly, the evolutionary relationships within the subfamilies remain ambiguous, and the genera in each are listed alphabetically. Subfamily Chelidonioideae Ernst includes genera 1-5; subf. Eschscholzioideae Ernst, genera 6-7; subf. Papavaroideae Ernst, genera 8-14; and subf. Platostamenoideae Ernst, genera 15-17.

Hunnemannia fumariifolia Sweet, native to the highlands of Mexico, is occasionally found in California as a garden escape. A glabrous perennial with glaucous, blue-gray stem and leaves, and glossy, yellow petals, it bears an overall resemblance to Eschscholzia but has distinct sepals, no receptacular cup, and a peltate stigma. Below, it would key out as Arctomecon .

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.