Neotropical Krameriaceae

Jon L.R. Every* and Amélia Baracat*

Royal Botanic Gardens, Kew, UK. 

Description

Shrubs (up to 6m tall) or herbs sometimes sprawling, hemiparasitic (no specific host) with green parts present, often densely indumented (strigose to tomentose) appearing golden or white. Leaves alternate, arranged both spirally and distichously, simple (except for trifoliate K. cytisoides Cav.), laminar margin entire, exstipulate, sessile or petiolate (sometimes minutely so).  Inflorescence terminal or axillary in panicles, racemes or solitary, peduncle and pedicle separated by a pair of bractlets. Flower hermaphroditic, zygomorphic; calyx with 5 pubescent, petaloid sepals; corolla with 5 dimorphic petals, 2 modified into secretory glands either side of the ovary, 3 reduced, forming a flag, inserted together at the base of the principal sepal, free, slightly fused at the base or connate up to 75% of their lengths and then clawed; stamens (3-)4, free to base or mostly connate, adnate to flag petals; anthers dehiscing via pores; ovary superior, bicarpellate, appearing unicarpellate, hirsute; style 1, usually glabrous.  Fruit globose or heart-shaped, dry, capsular, covered in spines (except K. grandiflora A. St.-Hil.) barbed or not; seed 1, small, endosperm lacking, often absent from fruit.

Notes on delimitation

  • Treated here as circumscribed by Simpson (1989) in Flora Neotropica.
  • A monotypic family in the Polygalales.
  • Previously placed in both in Polygalaceae and Leguminosae due to the shared characteristics such as zygomorphic flowers and poricidally dehiscing anthers.
  • Some authors drew further comparison between Krameria Loefl. and the legume family such as the compound leaf of K. cytisoides, the seemingly unicarpellate gynoecium, the fruit structure and pollen. By contrast the wood anatomy, ovule ontogeny, seed coat anatomy and chromosomal numbers clearly separate the two plant groups.

Distribution in the Neotropics

  • 11 of the 17 species occur throughout the Neotropics.
  • They are strictly located to open arid and semi-arid habitats as well as seasonally dry regions.
  • The majority of the species grow in eastern Mexico and east central Brazil below 1,500m.

Other South American species outside Brazil and Mexico:

  • In the Andes of Peru and Bolivia K. lappaceae  (Dombey) Burdet & B.B. Simpson can be found at altitudes up to 3,600m; and it is also found as far South as Jujuy in Andean Argentina.
  • The only species found in the West Indies is K. ixinie Loefl. which is abundant
    throughout the floristic region.
  • K. cytisoides Hokk. & Arn. grows only in Chile's Antofagasta (one of the driest places on Earth)
    at 100 to 1,550m.
  • K. spartioides Klotzsch ex O. Berg grows in Colombia, Venezuela and Suriname.

Distinguishing characters (always present)

Other important characters

  • Flowers are mainly pink or purple (yellow or yellow-green in K. revoluta O. Berg).
  • Petals are less conspicuous than the showy sepals and are roundish, rectangular or wedge-shaped appearing cupped and blistered.

Key differences from similar families

Characters not present in Krameriaceae are listed below:

Number of genera

  • One: Krameria.

Useful tips for generic identification

See above

Notable genera and distinguishing features

See above

Status

  • All species are native.
  • K. argentea Mart. ex Spreng. is endemic to the Brazilian Planalto in the states of Distrito Federal, Goias and Bahia.
  • K. bahiana B.B. Simpson is an endemic to Bahia in Brazil.

General notes

  • The oils secreted by the 2 modified petals are collected by visiting female bees of the genus Centris, and mixed with pollen (and nectar from other taxa as Krameria does not produce nectar) into a paste, and fed to their developing larvae.
  • Krameria species are dependent on the bees for pollination.
  • The 2 modified petals are unique within the angiosperms.

Important literature

Simpson, B.B. 1989. Krameriaceae. Flora Neotropica. Monograph 49. The New York Botanical Garden, New York

How to cite

Every, J.L.R. & Baracat, A. (2009). Neotropical Krameriaceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Krameriaceae.htm.