Including Chelidoniaceae, Chymaceae Dulac, Eschscholziaceae, Platystemonaceae
Habit and leaf form. Herbs (mostly), or trees to shrubs (a few shrubs or small treelets); laticiferous, or with coloured juice (usually, the juice milky, yellow, or red), or non-laticiferous and without coloured juice (e.g. Eschscholtzia, Platystemon with watery juice). Annual, or perennial; with neither basal nor terminal aggregations of leaves. The treelets pachycaul. Mesophytic. Leaves alternate (usually, though the floral leaves are sometimes opposite or whorled), or whorled (ostensibly, in Platystemon); spiral; petiolate to sessile; non-sheathing; simple. Lamina dissected (usually), or entire; usually pinnatifid (lobed or dissected), or much-divided (e.g. bipinnatisect); pinnately veined; cross-venulate. Leaves exstipulate; without a persistent basal meristem.
General anatomy. Plants with laticifers (articulated, anastomosing or not), or without laticifers.
Leaf anatomy. Hydathodes present (occasionally), or absent. Stomata anomocytic.
Minor leaf veins without phloem transfer cells (Mecanopsis).
Stem anatomy. Nodes unilacunar, or tri-lacunar. Primary vascular tissue comprising a ring of bundles, or in two or more rings of bundles; centrifugal. Cortical bundles absent. Medullary bundles absent. Secondary thickening absent (commonly), or developing from a conventional cambial ring. Xylem with libriform fibres; with vessels. Vessel end-walls simple. Wood parenchyma paratracheal (vasicentric to sparse). Sieve-tube plastids S-type.
Reproductive type, pollination. Hermaphrodite. Entomophilous.
Inflorescence, floral, fruit and seed morphology. Flowers solitary (mostly), or aggregated in `inflorescences'; in cymes and in racemes. The terminal inflorescence unit cymose, or racemose. Inflorescences terminal; racemes or dichasia. Flowers medium-sized, or large; odourless; regular, or somewhat irregular. The floral asymmetry involving the perianth (when manifest). Flowers cyclic; tetracyclic to pentacyclic to polycyclic. Floral receptacle developing an androphore, or developing a gynophore, or with neither androphore nor gynophore. Free hypanthium absent (usually), or present (Platystemon). Hypogynous disk absent.
Perianth with distinct calyx and corolla (usually), or sepaline (the corolla lacking in Macleaya); 6(-10); 1 whorled, or 3 whorled, or 4 whorled; anisomerous (calyx whorl reduced relative to corolla whorls). Calyx 2(-4); 1 whorled; polysepalous, or gamosepalous (sometimes basally connate, sometimes coherent into an operculum); unequal but not bilabiate, or regular (usually rather asymmetrical); not persistent (caducous); calyptrate, or not calyptrate; imbricate. Corolla 4, or 6, or 8, or 12, or 16; 2 whorled (often 2+2 or 3+3), or 3 whorled; polypetalous; imbricate and crumpled in bud; regular; yellow, or orange, or red, or pink, or blue; not spurred.
Androecium 4-6 (Meconella), or 16-200 (usually `many'). Androecial members usually maturing centripetally; free of the perianth; free of one another; 3-15 - whorled (generally indefinite in 2- or 3-merous, regularly alternating whorls). Androecium exclusively of fertile stamens. Stamens 4-6 (rarely), or 16-60; isomerous with the perianth (rarely), or diplostemonous to polystemonous. Anthers basifixed; non-versatile; dehiscing via longitudinal slits; tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or decussate. Anther wall initially with one middle layer, or initially with more than one middle layer. Tapetum glandular. Pollen grains aperturate; 3 - aperturate, or 4 - aperturate, or 6-8 - aperturate, or 9-15 - aperturate; colpate (mostly, tricolpate, rarely slightly colporoidate), or foraminate, or rugate; 2-celled.
Gynoecium 2(-100) (to `many'). Carpels isomerous with the perianth, or increased in number relative to the perianth. Gynoecium syncarpous; semicarpous (Platystemon), or eu-syncarpous (the stigmas often connate to form a discoid roof on the ovary); superior. Ovary 1 locular, or 2-20 locular (by intrusion of the placentas). Gynoecium when G2, transverse; non-stylate, or stylate. Stigmas as many as the placentas; dorsal to the carpels, or commissural, or dorsal to the carpels and commissural; often combined into a peltate structure; dry type; papillate; Group II type. Placentation when unilocular parietal (usually), or basal (Bocconia); when plurilocular, axile. Ovules in the single cavity when unilocular 1 (Bocconia), or 2-100 (usually `many'); when plurilocular, 2-50 per locule (few to `many'); horizontal, or ascending; with superior or lateral raphe; arillate, or non-arillate; anatropous, or campylotropous, or amphitropous; bitegmic; crassinucellate. Outer integument contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; persistent. Synergids hooked (with filiform apparatus). Endosperm formation nuclear. Embryogeny solanad (or irregular).
Fruit non-fleshy; more or less multiple (Platystemon), or not multiple; dehiscent (usually), or indehiscent (rarely), or a schizocarp (Platystemon); a capsule (usually), or a silicule, or a siliqua, or a nut (rarely). Capsules poricidal, or septicidal, or valvular. Seeds copiously endospermic. Endosperm oily. Embryo rudimentary at the time of seed release (sometimes), or weakly differentiated. Cotyledons 2. Embryo achlorophyllous (7/8).
Seedling. Germination phanerocotylar, or cryptocotylar.
Physiology, biochemistry. Cyanogenic, or not cyanogenic. Cynogenic constituents tyrosine-derived. Alkaloids present (nearly always), or absent. Berberine present (at least in Argemone), or absent. Iridoids absent. Proanthocyanidins absent. Flavonols present; kaempferol, or quercetin, or kaempferol and quercetin. Ellagic acid absent (6 species, 6 genera). Arbutin absent. Aluminium accumulation not found. C3. C3 recorded in Argemone, Macleaya.
Geography, cytology. Frigid zone to sub-tropical. Mainly North temperate, but also in Iceland, Central America and West Indies, South Africa and Eastern Australia. X = (5-)6, 7, 8, 11, 19.
Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren's Superorder Ranunculiflorae; Papaverales. Cronquist's Subclass Magnoliidae; Papaverales. Takhtajan's Subclass Ranunculidae; Ranunculanae; Papaverales. Species 200. Genera 23; Arctomecon, Argemone, Bocconia, Canbya, Chelidonium, Dendromecon, Dicranostigma, Eomecon, Eschscholzia, Glaucium, Hunnemannia, Hylomecon, Macleaya, Meconella, Mecanopsis, Papaver, Platystemon, Platystigma, Roemeria, Romneya, Sanguinaria, Stylomecon, Stylophorum.
Economic uses, etc. Unripe capsules of Papaver somniferum supply commercial opium, and numerous species from Papaver, Meconopsis, Argemone, etc. are cultivated as ornamentals.
Illustrations. papav214.gif papav215.gif papav216.gif
Additional, to be intercalated. Flowers calyptrate, or not calyptrate.
