Jon L.R. Every* and Amélia Baracat*
Royal Botanic Gardens, Kew, UK.
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:
Distinguishing characters (always present)
- Densely pubescent leaves.
- Zygomorphic flowers.
- Two modified petals flank the hirsute ovary.
- Poricidally dehiscing anthers.
- Spiny single-seeded fruit with amber-colored barbs.
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:
- Leguminosae: stipules, 10+ stamens, fruit a legume.
- Polygalaceae: distinct sepals, 10+ stamens, nectary at base of ovary, seed with abundant endosperm.
Number of genera
- One: Krameria.
Useful tips for generic identification
Notable genera and distinguishing features
- 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.
- 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.
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.
Click images to enlarge
Krameria argentea (herbarium specimen) © Board of Trustees of the Royal Botanic Gardens, Kew.
Flower of Krameria cytisoides © Nigel Taylor, RBG, Kew
Krameria cytisoides (herbarium specimen) © Board of Trustees of the Royal Botanic Gardens, Kew.
Krameria grandiflora (herbarium specimen) © Board of Trustees of the Royal Botanic Gardens, Kew.
Krameria spartioides (herbarium specimen) © Board of Trustees of the Royal Botanic Gardens, Kew.
Flower of Krameria sp. © John Wood/Darwin Initiative Project 161/11/011.