Neotropical Picramniaceae

Jon L.R. Every

University of Plymouth, U.K. 

Description

Dioecious trees and shrubs, bark contains bitter-tasting anthraquinones. Leaves alternate, spiral, compound, imparipinnate, exstipulate. Inflorescence axillary, pendulous, catkin-like racemes or spikes, rarely cauliflorous, <30 cm long. Flowers actinomorphic, unisexual, dioecious, small, 3-5(-6)merous; sepals free to slightly connate at base, imbricate or valvate, persistent; petals caducous, absent in staminate flowers; stamens equapetalous in number and alternatisepalous, ocasionally on a column; ovary superior, gynophore present; carpels 2-3, fused, locules 1-3, ovules 2 per locule, stigma sessile, 2-3. Fruit a berry in Picramnia Sw., a samara in Alvaradoa Liebm.

Notes on delimitation

  • Treated as two distict subfamilies the Picraminioideae and the Alvaradooideae due to the differences in fruit and ovary morphology.
  • Long incorporated in the Simaroubaceae but now separated by fruit and molecular differences.
  • Current evidence places the family in a newly recognized order: the Picramniales in the Rosid II/Malvid clade (APGIII).

Distribution in the Neotropics

From Mexico south to northern Argentina.

  • Alvaradoa is absent from all of the Amazon Basin except the extreme south and is concentrated in arid regions.
  • Three of five Alvaradoa species are single island endemics found on the Caribbean Islands of Cuba, Hispanola and Jamaica.
  • Picramnia is found primarily in rainforest areas with some species adapting to the drier areas of the Brazilian Planalto.

Key differences from similar families

  • Differing from members of the Simaroubaceae s.s in not having uniovulate locules.

Number of genera

  • Two: Picramnia 41 spp., Alvaradoa 5 spp.

Useful tips for generic identification

  • Fruit a berry in Picramnia, a samara in Alvaradoa.  
  • Carpels only 1 fertile in Alvaradoa, 2 - 3 in Picramnia.
  • Ovules terminal and pendulous in Picramnia, basal and erect in Alvaradoa.  

Status

  • Endemic to the Neotropics.

Important literature

APG III. 2009. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants. Botanical Journal of the Linnean Society. Vol 161: 3. Pp. 105-121.

Brummitt, R.K. 2007. Picramniaceae. In: V.H. Heywood, R.K. Brummitt, A. Culham and O. Seberg (eds.). Flowering plant families of the world. Pp. 253-254. Royal Botanic Gardens, Kew.

Mabberley, D.J. 2008. Mabberley's plant book. Third edition. Cambridge University Press, Cambridge.

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

Thomas, W.W. 2004. Picramniaceae. In: Smith, N., Mori, S.A., Henderson, A., Stevenson, D.W. and Heald, S.V. (eds). Flowering Plants of the Neotropics. Pp. 294-295. The New York Botanical Garden, Princeton University Press, Princeton.

Watson, L. and Dallwitz, M.J. (1992 onwards). The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version 3rd March 2009. http://delta-intkey.com

How to cite

Every, J.L.R. (2010). Neotropical Picramniaceae. 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/Picramniaceae.htm.