Neotropical Haptanthaceae

Description

Evergreen broad-leaved tree (or shrub?). Leaves opposite, simple, entire, glabrous; estipulate. Inflorescence axillary, cymose, pedunculate. Flowers unisexual, monoecious, bracteate; staminate flowers with 2 leaf-like stamens and tepals absent, or 2 tepals with adnate stamens, anthers dehiscing via longitudinal slits, dorsifixed; pistillate flowers with 4 tepals, ovary superior, syncarpous, carpels 3, placentation parietal, stigmas 3. Fruit unknown.

Notes on delimitation

• Described in 1989 as Haptanthus hazlettii Goldberg & C. Nelson and placed in its own family.
• Placed in the Buxales by the APG on morphological grounds (Stevens 2008).

Distribution in the Neotropics

• Found on a single occasion in the rainforest of central Honduras in 1980, rediscovered in April 2010.

Distinguishing characters (always present)

• Evergreen.
• Monoecious.
• Staminate flowers with two elliptic flattened structures.

Key differences from similar families

• The single collection has been compared to many families but due to the lack of information it has proved very difficult to identify distinct differences. The morphology of the flowers appears to be distinct from the listed families: Achariaceae, Buxaceae, Capparaceae, Chloranthaceae, Euphorbiaceae, Hamamelidaceae, Lacistemataceae, Salicaceae, Saururaceae. 
   

Number of genera

• 1: Haptanthus hazlettii.

Important literature

Goldberg, A. & Nelson, C. 1989. Haptanthus, a New Dicotyledonous Genus from Honduras. Systematic Botany: 14(1): 16-19.

Heywood, V.H. 2007. Haptanthaceae. In: V.H. Heywood, R.K. Brummitt, A. Culham and O. Seberg (eds.). Flowering plant families of the world. P.164. Royal Botanic Gardens, Kew.

Maas, P.J.M. & Westra, L.Y.Th. 2005. Neotropical Plant Families. 358 pp. 3rd ed. A.R.G. Gantner Verlag K.G., Ruggell.

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

Stevens, P.F. & Doust, A.N. 2005. A Reinterpretation of the Staminate Flowers of Haptanthus. Systematic Botany 30(4): 779-785.

How to cite

Every, J.L.R. (2009). Neotropical Haptanthaceae. 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/Haptanthaceae.htm.