Neotropical Euphroniaceae

Paul J.M. Maas & Hiltje Maas-van de Kamer

National Herbarium of the Netherlands (Wageningen branch), Wageningen, the Netherlands.

Description

Shrubs or small trees.  Leaves alternate, simple, lower surface covered with greyish white hairs; stipules small, soon falling off.  Inflorescences terminal or axillary racemes.  Flowers bisexual, zygomorphic; sepals 5, imbricate, connate at the base, unequal; petals 3, purplish, contorted, free, clawed; stamens 4, connate at the base, in 2 opposite pairs, the pairs separated on one side by 1 long staminode and on the other side by 1-5 small, dentate staminodes, anthers dithecal, longitudinally dehiscent; ovary superior, 3-locular, style 1, stigma 1, 3-lobed, placentation axile, ovules 2 per locule.  Fruits septicidal capsules, with persistent sepals and androecium.  Seeds 1 per locule, slightly winged at the base.

Notes on delimitation

  • The family Euphroniaceae is placed in the order Malpighiales, closest to Chrysobalanaceae in the APG III classification (Stevens, 2008; APG III, 2009).  Takhtajan (1997) placed the family in the Chrysobalanales, together with Trigoniaceae, Dichapetalaceae and Chrysobalanaceae.  It was considered by Cronquist (1982) as part of the Vochysiaceae, while Marcano-Berti (1989) segregated the genus Euphronia and gave it family status.

Distribution in the Neotropics

  • A monotypic family restricted to the Neotropics.  In savannas on white sand or rocky areas, or on exposed sandstone outcrops, or in riparian forests; at elevations of 100-1,400(-2,000) m.
  • Euphronia Mart. & Zucc. (3 spp.) - The Guayana Shield of Colombia, Venezuela, Guyana, and Brazil.

Distinguishing characters (always present)

Other important characters

Key differences from similar families

Superficially resembling Vochysiaceae and Trigoniaceae, but keyed out as follows:

1. Leaves alternate (but see also Trigoniodendron) …. Euphroniaceae
1. Leaves opposite or in whorls …. 2.

2. Calyx spurred; petals 0-5, without a spur; leaves opposite or whorled; trees …. Vochysiaceae
2. Calyx without a spur; petals 5, one of which is spurred; leaves opposite, very rarely alternate (Trigoniodendron from SE Brazil); lianas, shrubs, very rarely trees (Trigoniodendron) …. Trigoniaceae.

From Chrysobalanaceae it can be keyed out as follows:

1. Petals 3; staminodes present; ovary 3-locular; fruit a 1-seeded capsule … Euphroniaceae
1. Petals 5; staminodes absent; ovary 1-2-locular; fruit a drupe … Chrysobalanaceae

Status

  • Euphronia is native in the Neotropics.
  • The genus is not cultivated, nor of any economic importance.

General notes

  • The seeds are probably wind-dispersed.

Important literature

A.P.G. III. 2009. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III. Bot. J. Linnean Soc. 161: 105-121.

Cronquist, A. 1981. An integrated system of classification of flowering plants. Columbia University Press. New York

Maas, P.J.M. & Westra, L.Y.Th. 2005. Neotropical Plant Families. A concise guide of vascular plants in the Neotropics. 3rd ed., p. 191. A.R.G. Gantner Verlag K.G., Ruggell.

Marcano-Berti, L. 1989. Euphroniaceae: Una nueva familia. Pittieria 18: 15-19.

Marcano-Berti, L. 1998. Euphroniaceae. In: Görts-van Rijn, A.R.A. & Jansen-Jacobs, M.J. (eds.), Flora of the Guianas vol. 21, pp. 45-48. Royal Botanic Gardens, Kew.

Stevens, P.F. 2008. Angiosperm Phylogeny Website. Version 9 onwards. http://www.mobot.org/MOBOT/research/APweb/.

Steyermark, J.A. & Marcano-Berti, L. 1999. Euphroniaceae. In: Berry, P.E. Yatskievych, K. and Holst, B. (eds.). Flora of the Venezuelan Guayana vol. 5, pp. 228-230. Missouri Botanical Garden Press.

Takhtajan, A. 1997. Flowering Plants. Second edition. Springer.

How to cite

Maas, P.J.M. & Maas-van de Kamer, H. (2012). Neotropical Euphroniaceae. 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/Euphroniaceae.htm.