Neotropical Papaveraceae

Sara L. Edwards

Royal Botanic Gardens, Kew, U.K.


Habitannual, biennial or perennial herbs or pachycaulous treelets (Bocconia L.) with orange, yellow, white or watery latex. Leaves usually alternate, occasionally subopposite or whorled (in Fumarioideae), petiolate to sessile, simple, entire to ternately divided; stipules absent. Inflorescences terminal or axillary, paniculate or racemose, or flowers solitary. Flowers bisexual, actinomorphic (in Papaveroideae) or zygomorphic (in Fumarioideae), often nodding when in bud, sometimes erect; sepals 2-3, caducous, herbaceous or small, petaloid (in Fumarioideae); petals 4-6; ovary superior, syncarpous, two to many carpellate; stamens usually many, free, arising centripetally or 2 (in Fumarioideae). Fruits one- (Bocconia) to usually many-seeded capsules or nuts (Fumaria L.). Seeds usually small.

Notes on delimitation

  • In the APG III classification system (Stevens, 2001 onwards) the three families Papaveraceae, Fumariaceae and Pteridophyllaceae (monotypic and endemic to Japan) that used to comprise the order Papaverales (Cronquist 1981; Dahlgren 1989) are now all included within Papaveraceae.  Additionally, in the APG III system Papaverales are not considered to be an order, and the Papaveraceae are placed in the order Ranunculales (Steven 2001 onwards).

Distribution in the Neotropics

Worldwide the Papaveraceae comprise 41 genera and ca. 700 species. Of these ca. 13 genera and ca. 58 species occur in the Neotropics. Representation of genera:

  • Argemone L.: (ca. 25 species) mostly from North America and North Mexico, but also with a small centre of diversity in Chile with ca. 7 species, 4 of which do not occur in Mexico. Argemone mexicana L. is the most widespread species and has been recorded in most Central and South America countries and the Caribbean, except Colombia and the Galapagos Islands.
  • Bocconia L.: (7 species) along the west coast of South America from Northern Mexico to Northern Argentina, and in the West Indies.
  • Chelidonium L.: (1 species) Chelidonium majus L. introduced from Eurasia, only recorded from Peru and Argentina.
  • Corydalis DC.: (1 species) Corydalis aurea Willd. North America extending south into Mexico.
  • Dendromecon Benth.: (1 species) Dendromecon rigida Benth. in Western North America and Baja California in Mexico.
  • Eschscholzia Cham. (3 species) mostly North American but 3 species extend south into Mexico. Eschscholzia californica Cham. also occurs in Ecuador, Argentina and Chile.
  • Fumaria L.: (6 species) mostly weeds of Mediterranean origin, extending from Mexico along western Central and South America to Argentina and Chile.
  • Glaucium Mill.: (2 species) in Argentina, introduced from Atlantic Europe and Central Asia.
  • Hunnemannia Sweet: (2 species) Hunnemannia fumariifolia Sweet is endemic to Mexico and H. hintoniorum Sweet is southern North America, Mexico and Honduras.
  • Papaver L. (7 species) mostly from the Northern hemisphere, but several species are widely cultivated.
  • Platystemon Benth. (1 species) Platystemon californicus Benth. mainly in North America but extends into adjacent Baja California, Mexico.
  • Romneya Harv. (1 species) Romneya trichocalyx Eastw. from adjacent California and Baja California, Mexico.
  • Stylomecon G. Taylor (1 species) Stylomecon heterophylla (Benth.) G. Taylor from adjacent California and Baja California, Mexico.

Distinguishing characters (always present)

Key differences from similar families

Number of genera

  • 41 genera (see Distribution in the Neotropics above).

Useful tips for generic identification

Key to the Neotropical genera of the Papaveraveae
A combination of keys in Kadereit (1993) and Lidén (1993), modified to include only the genera that occur in the Neotropics.

1. Flowers zygomorphic. Sepals 2, petaloid... 2
1. Flowers actinomorphic. Sepals 2-3 usually green and herbaceous... 3

2. Fruit a single-seeded nut. Seeds brown. Style caducous. Stigma two big papillae ... Fumaria
2. Fruit a many-seeded dehiscent capsule. Seeds black. Style persistent. Stigmas usually flattened with marginal papillae ... Corydalis

3. Corolla absent. Fruit a single-seeded capsule. Usually pachycaulous trees, sometimes shrubs ... Bocconia
3. Corolla present. Fruit a many-seeded dehiscent capsule. Usually herbs, sometimes shrubs ... 4

4. Ovary bicarpellate ... 5
4. Ovary with 3-25 carpels ... 9

5. Mature capsules with 10 conspicuous longitudinal veins. Fruit dehisces explosively. Stigmas sessile. Hairs unicellular, when present ... 6
5. Mature capsules without 10 conspicuous longitudinal veins. Fruit dehiscence never explosive. Stigmas on a short style. Hairs multicellular, when present ... 8

6. Evergreen woody shrubs. Leaves undivided ... Dendromecon
6. Annual or perennial herbs. Leaves many-lobed... 7

7. Sepals united ... Eschscholzia
7. Sepals free... Hunnemannia

8. Inflorescence an umbel, flowers supported by small entire bracts ... Chelidonium
8. Flowers solitary ... Glaucium

9. Leaves linear, margin entire. Fruits breaking into 1-seeded mericarps. Carpel tips and stigmas free... Platystemon
9. Leaves pinnately incised or divided. Fruits opening by basipetal valves. Carpel tips united, stigmas of neighbouring carpels confluent ... 10

10. Style distinct. Capsular fruit, the base of the style flattened into a disk at the top of the capsule... Stylomecon
10. Stigmas sessile or on a short style. Capsular fruit without a style or if they have a style, then not flattening into a disk ... 11

11. Sepals with distinct stiff, apical horns. Seeds orbicular. Stigmas usually on a short style... Argemone
11. Sepals without distinct stiff, apical horns. Seeds irregularly angular to ellipsoid or reniform. Stigmas sessile... 12

12. Stigmas linear, fused into a flat to conical disc, sometimes deeply furrowed between the individual stigmas. Ovary clavate to globose. Fruits opening by basipetal pores or short valves below the disc. Seeds reniform... Papaver
12. Stigmas not fused into a disc. Placentae fused into a central column. Ovary ovoid. Fruits opening by basipetal valves up to ˝ the length of the fruit.  Seeds irregularly angular or ellipsoid... Romneya

Notable genera and distinguishing features

  • Argemone: Sepals with stiff conspicuous apical horns. (Common name 'Horned Poppy').
  • Bocconia: Pachycaulous trees 2-6 m tall. Calyx of 2 sepals, corolla absent. Fruit single-seeded.
  • Eschscholzia: Sepals fused. Gynoecium bicarpellate. Fruits with 10 conspicuous longitudinal ribs, dehiscing explosively.
  • Fumaria: Glabrous. Flowers zygomorphic. Stigma with two large papillae. Fruit a single-seeded nut.
  • Hunnemannia: Sepals free. Gynoecium bicarpellate. Fruits with 10 conspicuous longitudinal ribs, dehiscing explosively.
  • Papaver: Stigmas sessile, linear, arranged into a conical or flat disc. Fruit a capsule dehiscing from pores or short valves just below the stigmatic disc.


  • Papaveraceae is mainly a northern temperate family. Some species such as Eschscholzia californica Cham. (Californian Poppy) have been introduced as ornamentals to many areas of the Neotropics. However some genera such as Hunnemannia and Argemone are native. Hunnemannia has one species endemic to eastern Mexico and the other with a slightly wider distribution spreading into North America and south into Honduras.

General notes

  • The exudates of Papaver somniferum L. and P. bracteatum Lindl. to a lesser extent, are used to make pharmaceuticals such as codeine, opium, morphine and heroine.
  • Many other species of Papaveraceae are used in herbal medicine and considered cure alls, treating wide ranging ailments from removing warts to making sedatives, expectorants or purgatives.
  • The latex of both Argemone and Bocconia can be used as dyes.
  • Papaveraceae are widely cultivated as ornamentals.

Important literature

Grey-Wilson, C. 2000. Poppies: The Poppy Family in the Wild and in Cultivation. B.T. Batsford, London.

Kadereit, J.W. 1993. Papaveraceae. In: Kubitzki, K., Rohwer, J.G. & Bittrich, V. (eds.). The Families and Genera of Vascular plants vol. II, pp. 494-506. Springer-Verlag, Berlin.

Lidén, M. 1993. Fumariaceae. In: Kubitzki, K., Rohwer, J.G. & Bittrich, V. (eds.). The Families and Genera of Vascular plants vol. II, pp. 310-318. Springer-Verlag, Berlin.

Lidén, M. 1995. Papaveraceae. In: G. Harling & L. Anderson (eds) Flora of Ecuador 69. 1-13. Department of Plant and Environmental Sciences, University of Gothenburg.

Stein, B.A. 2001. Papaveraceae. In: Stevens, W.D., Ulloa Ulloa, C., Pool, A., Montiel, O.M. (eds.). Flora de Nicaragua vol. 85(III), pp. 1911-1913.Missouri Botanical Garden Press.

Stevens, P. F. 2001 onwards. Angiosperm Phylogeny Website. Version 12, July 2012 [and more or less continuously updated since].

Thornton-Wood, S.P. 2011 Papaveraceae. Flora Mesoamericana, vol. 2(1).

How to cite

Edwards, S.L. (2014). Neotropical Papaveraceae. In: Milliken, W., Klitgĺrd, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics.