Papaver L.

Scientific Description

Family Papaveraceae.

Habit and leaf form. Herbs; laticiferous, or with coloured juice (the juice milky or yellow). Plants unarmed. Annual to perennial; plants with a basal concentration of leaves. Mesophytic. Leaves alternate; spiral; petiolate to sessile; non-sheathing; simple. Leaf blades dissected, or entire; when dissected, pinnatifid (or lobed), or much-divided (bipinnatisect); pinnately veined; cross-venulate. Leaves without stipules; without a persistent basal meristem. Leaf anatomy. Hydathodes present, or absent. Hairs present, or absent (rarely). Stem anatomy. Nodes unilacunar, or tri-lacunar. Secondary thickening absent, or developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous.

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’; when aggregated, in raceme-like cymes. The terminal inflorescence unit cymose, or racemose. Inflorescences terminal. Flowers medium-sized, or large (often showy, buds frequently drooping); operculate (calyptrate), or not operculate; odourless; 2 merous, or 3 merous; tetracyclic to pentacyclic to polycyclic. Floral receptacle developing an androphore, or developing a gynophore, or with neither androphore nor gynophore. Free hypanthium absent. Hypogynous disk absent. Perianth with distinct calyx and corolla; 6, or 9; 3 -whorled; isomerous. Calyx 2, or 3; 1 -whorled; polysepalous; imbricate; unequal but not bilabiate, or regular (? rather asymmetrical); not persistent (caducous). Corolla 4, or 6; 2 -whorled (2+2 or 3+3); polypetalous; imbricate and crumpled in bud; regular; white, or yellow, or orange, or red, or pink; not spurred. Androecium 50–100 (i.e. ‘many’). Androecial sequence determinable, or not determinable. Androecial members 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 50–100 (i.e. ‘many’); polystemonous. Anthers basifixed; non-versatile; dehiscing via longitudinal slits; tetrasporangiate. Gynoecium 4–24 carpelled. The pistil 1 celled. Carpels increased in number relative to the perianth. Gynoecium syncarpous; synstylovarious to eu-syncarpous (depending on interpretation of confluent stigmas); superior. Ovary unilocular; 1 locular. Locules secondarily divided by ‘false septa’, or without ‘false septa’. Gynoecium non-stylate (stigmas sessile). Stigmas 4–24; dorsal to the carpels, or commissural, or dorsal to the carpels and commissural; dry type; papillate; Group II type. Placentation parietal. Ovules in the single cavity 20–50 (i.e. ‘many’); horizontal, or ascending; with superior or lateral raphe; arillate, or non-arillate; anatropous, or campylotropous, or amphitropous.

Fruit and seed features. Fruit non-fleshy; dehiscent; a capsule (subglobular, ovoid, clavate or cylindric, crowned with persistent stigmatic disc). Capsules poricidal (by basipetal pores or short valves below disc, or disc caducous). Fruit many seeded. Seeds reniform; copiously endospermic. Endosperm oily. Embryo rudimentary at the time of seed release, or weakly differentiated. Cotyledons 2. Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, biochemistry. Aluminium accumulation not found. Photosynthetic pathway: C₃.

Geography, cytology, number of species. Adventive. Australian states and territories: Western Australia, South Australia, Northern Territory, Queensland, New South Wales, Victoria, Australian Capital Territory, and Tasmania. South-West Botanical Province.

Economic uses, etc. Unripe capsules of Papaver somniferum supply commercial opium, and numerous species are cultivated as ornamentals.

Additional characters Stigmas the stigmatic area linear (arranged in conical or flat disc over placentae).