Euphroniaceae Marc.-Berti

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

Morphology

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.

General Description

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.

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.

Distribution

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.

Diagnostic

Distinguishing characters (always present)

• Leaves alternate with the lower surface densely covered with greyish white hairs.
• Flowers zygomorphic, petals 3, clawed, stamens 4 in 2 pairs, 1-6 staminodes present; ovarysuperior, 3-locular.
• Fruit a 1-seeded capsule crowned by the sepals and androecium.

Other important characters

• Seeds basally winged.

Key differences from similar families

Superficially resembling Vochysiaceae and Trigoniaceae, but keyed out as follows:1. Leaves alternate (but see also Trigoniodendron) .. Euphroniaceae1. Leaves opposite or in whorls .. 2.

2. Calyx spurred; petals 0-5, without a spur; leaves opposite or whorled; trees .. Vochysiaceae2. 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 . Euphroniaceae1. Petals 5; staminodes absent; ovary 1-2-locular; fruit a drupe . Chrysobalanaceae

Literature

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.