Sp. Pl. 1: 506. 175.
Gen. Pl. ed. 5, 224. 1754.
Herbs, annual, biennial, or perennial, scapose or caulescent, from taproots; sap white, orange, or red. Stems when present leafy. Leaves: basal rosulate, petiolate; cauline alternate, proximal leaves petiolate, distal subsessile or sessile, sometimes clasping (in P. somniferum); blade unlobed or 1-3× pinnately lobed or parted; margins entire or toothed, scalloped, or incised. Inflorescences cymiform, with flowers disposed in 1s, 2s or 3s on long scapes or peduncles; bracts present; buds nodding [erect]. Flowers: sepals 2(-3), distinct; petals 4(-6); stamens many; pistil 3-18[-22]-carpellate; ovary 1-locular, sometimes incompletely multilocular by placental intrusion; style absent; stigmas 3-18[-22], radiating on sessile, ± lobed disc, velvety. Capsules erect, 3-18[-22]-pored or short-valved immediately beneath persistent or sometimes deciduous (in P. hybridum) stigmatic disc. Seeds many, minutely pitted, aril absent. x = 7.
Temperate and arctic North America, Eurasia, n, s Africa, Australia.
Species 70-100 (16 in the flora).
Papaver is rich in alkaloids, notably opiates. The genus is quite complex cytologically; in addition to diploids, there are numerous polyploid species and some that apparently are aneuploid. Most commonly, n = 7 or a multiple, and 2n ranges from 14 to over 100. There are published chromosome counts for almost every taxon in the flora, but for the introduced species none has been made from wild-collected North American material.
The scapose poppies in the flora are native; the caulescent ones, except Papaver californicum, are introduced Eurasian ornamentals, crop weeds, and ballast waifs. All the scapose species are confined to arctic and alpine habitats. Plants of the introduced caulescent species, especially P. rhoeas, P. dubium, and P. somniferum, vary greatly in size, and surprisingly diminutive mature individuals are sometimes found, especially northward.
Papaver dahlianum Nordhagen, Bergens Mus. Årbok 2: 46. 1931
Papaver radicatum Rottbfll subsp. dahlianum (Nordhagen) Rändel
We regard this species as being restricted to arctic Europe, a narrower circumscription than U. Rändel's (1977).
Papaver microcarpum de Candolle, Syst. Nat. 2: 71. 1821
We are so far unable to substantiate D. Löve's (1969) report of this essentially Asiatic species "from Seward and Kenai peninsulas in Alaska, the Aleutian Islands."
|1||Plants caulescent (sometimes subscapose), at least a few cauline leaves present.||> 2|
|1||Plants strictly scapose, leaves all basal (sect. Meconella).||> 8|
|2||Blades of distal leaves clasping stem (sect. Papaver).||Papaver somniferum|
|2||Blades of distal leaves not clasping stem.||> 3|
|3||Capsules setose (sect. Argemonideum).||> 4|
|3||Capsules glabrous.||> 5|
|4||Capsules obovoid-ellipsoid to subglobose, densely and firmly setose.||Papaver hybridum|
|4||Capsules oblong to clavate, sparsely and weakly setose.||Papaver argemone|
|5||Plants perennial; flowers 10 cm or more broad (sect. Macrantha).||Papaver orientale|
|5||Plants annual; flowers less than 10 cm broad.||> 6|
|6||Peduncles glabrous or sparsely pilose; petals with greenish basal spot; stigmatic disc conic, usually umbonate; capsules distinctly short-valvate (sect. Californicum).||Papaver californicum|
|6||Peduncles hispid; petals unspotted or with dark basal spot; stigmatic disc ± flat; capsules poricidal (sect. Rhoeadium).||> 7|
|7||Peduncles markedly spreading-hispid distally; capsules less than 2 times longer than broad.||Papaver rhoeas|
|7||Peduncles strongly appressed-hispid distally; capsules 2 times or more longer than broad.||Papaver dubium|
|8||Leaf blades mostly with 3 primary lobes.||Papaver walpolei|
|8||Leaf blades with 5–many primary lobes.||> 9|
|9||Capsules more than 4 times longer than broad.||Papaver macounii|
|9||Capsules 1–2.5 times longer than broad.||> 10|
|10||Trichomes on capsules ivory colored.||> 11|
|10||Trichomes on capsules light to dark brown or black.||> 13|
|11||Plants tall, seldom less than 2 dm.||Papaver nudicaule|
|11||Plants short, seldom more than 1.5 dm.||> 12|
|12||Leaf blades setose.||Papaver alboroseum|
|12||Leaf blades glabrous or sparsely hirsute.||Papaver pygmaeum|
|13||Leaf blades mostly with 5 primary lobes, lobes mostly simple.||> 14|
|13||Leaf blades with more than 5 primary lobes, lobes mostly divided.||> 15|
|14||Primary leaf lobes oblanceolate to strap-shaped.||Papaver gorodkovii|
|14||Primary leaf lobes broadly lanceolate to ovate.||Papaver radicatum|
|15||Scapes straight, erect, generally longer than 20 cm; capsules oblong-ellipsoid.||Papaver lapponicum|
|15||Scapes curved, erect or decumbent, less than 15 cm, capsules obconic to subglobose.||> 16|
|16||Leaf blades generally green, not glaucous, primary lobes lanceolate, their apices acute to obtuse.||Papaver radicatum|
|16||Leaf blades generally gray- and blue-green, glaucous, primary lobes obovate to strap-shaped, their apices rounded.||Papaver mcconnellii|