Neotropical Bonnetiaceae

Mats H.G. Gustafsson

Department of Biological Sciences, Aarhus University, Denmark.

Description

Glabrous shrubs or trees with alternate, entire leaves. Flowers solitary or inflorescence cymose; sepals 5; petals 5, free, contorted, white or pink; stamens numerous, sometimes in 5 antepetalous fascicles; anthers basifixed; ovary superior, consisting of 3 - 5 carpels; styles free or basally fused; placentation central. Fruit a septicidal capsule with 3-5 locules. Seeds small and numerous, often winged.

Notes on delimitation

  • The Bonnetiaceae are related to the Clusiaceae and its segregate families Calophyllaceae and Hypericaceae.
  • In this group of families also belong the Podostemaceae, a group of highly specialized aquatics found in fast-flowing streams.
  • The closest relatives of the Bonnetiaceae are, according to the most recent molecular results, the Clusiaceae sensu stricto.

Distribution in the Neotropics

  • Most species of Bonnetiaceae are confined to the Guayana region, but the Northern Andes, Eastern Brazil and Cuba have one species each.

Distinguishing characters (always present)

  • Leaves are spirally inserted, entire, exstipulate and sessile to subsessile. Leaf margins are either smooth or finely serrate. Buds are somewhat pointed. Stamens are numerous and basifixed.

Other important characters

Key differences from similar families

Number of genera

  • Two: Archytaea Mart &BonnetiMart.

Useful tips for generic identification

Key to genera of Neotropical Bonnetiaceae

1. Stamens in fascicles; ovary 3-locular ... Archytaea
1. Stamens not in fascicles; ovary 4-5-locular ... Bonnetia

Notable genera and distinguishing features

  • Bonnetia, with  about 30 neotropical species, is a characteristic component of the vegetation of the tepuis, the sandstone plateaus of the Guayana shield. They are often small trees with leaves that may resemble those of monocotyledons in being sessile with parallel veins (actually secondary veins parallel to the midvein).

Status

  • Native.

Important literature

Ruhfel, B., V. Bittrich, C. Bove, M. H. G. Gustafsson, C. Philbrick, R. Rutishauser, Z. Xi and C. Davis. 2011. Phylogeny of the Clusioid clade (Malpighiales): evidence from the plastid and mitochondrial genomes. American Journal of Botany 98: 306-325.

Stevens, P. F. 2007. Hypericaceae. In K. Kubitzki (ed.) Families and Genera of Vascular Plants. Volume IX: 194-201.

Steyermark, J. A. 1984. Theaceae (Bonnetiaceae). In: Flora of the Venezuelan Guayana, I. Annals of the Missouri Botanical Garden 71: 297-340.

How to cite

Gustafsson, M.H.G. (2013). Neotropical Bonnetiaceae. 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/Bonnetiaceae.htm.