Neotropical Loganiaceae

Daniela Zappi

Royal Botanic Gardens, Kew, UK. 

Description

Herbs, climbers, lianas, shrubs, trees. Leaves opposite, sometimes whorled, entire, linked by interpetiolary relatively small stipules, tendrils and spines sometimes present. Inflorescences cymose, terminal or axillary, rarely flowers solitary (Gelsemium Juss.), bracts rarely present, scamose and in several series in Antonia Pohl. Flowers perfect, often heterostylic; calyx fused or free to the base, lobes generally acute; corolla gamopetalous, aestivation valvar or imbricate, symmetry radial, small, to 8 cm long, white, cream, yellow, lilac, pink or magenta, glabrous to hairy outside or bearded within (Strychnos L.), stamens alternate with the corolla-lobes, stigma simple or bifid, ovary generally bilocular, sometimes with 1 or 5 loci. Fruits capsular or berry-like; seeds 1-numerous, rounded, flat, angled or winged.

Notes on delimitation

  • Includes Strychnos (Strychnaceae) and Gelsemium and Mostuea Didr. (Gelsemiaceae); excludes Potalia Aubl. (Potaliaceae or Gentianaceae), Buddleja L. (Buddlejaceae or Scrophulariaceae).

Distribution in the Neotropics

Throughout the Neotropics, not very extensive in dryland vegetation:

  • Antonia ovata Pohl (monotypic genus from Eastern Brazil to the Amazon basin).
  • Bonyunia M.R.Schomb. (Amazonian).
  • Gelsemium (Pantropical with two species in Southern USA reaching Central America).
  • Mitreola L. (Neotropical weed).
  • Mostuea (mostly Paleotropical, with one species in Southeastern Brazil and another in the Guianas).
  • Spigelia L. (Neotropical, very diverse in Eastern Brazil).
  • Strychnos (Pantropical but very extensive in the Amazon basin).

Distinguishing characters (always present)

Other important characters

  • Internal phloem.
  • Cymose inflorescences sometimes helicoid or scorpioid.

Key differences from similar families

Number of genera

  • 20 genera and over 700 species worldwide, of which approximately 7 genera and 400 species are Neotropical.

Useful tips for generic identification

Notable genera and distinguishing features

  • Strychnos (large woody lianas with tendrils and sometimes spines, trinerveous leaves and berries).
  • Spigelia (herbs to subshrubs with scorpioid inflorescences, flowers often colourful and showy, sometimes leaves very reduced or lacking).
  • Antonia (trees with many series of bracts subtending each flower, resembling Asteraceae).
  • Gelsemium (climbers with solitary flowers).

Status

  • Cultivated species of Gelsemium have showy flowers.
  • Mitreola is a worldwide weed.
  • Spigelia anthelmia L. is cultivated as a medicinal plant.
  • Species of Spigelia in Eastern Brazil have endemic distribution.

General notes

  • A basal group in relation to Rubiaceae, Apocynaceae and Gentianaceae, it is not an easy family to characterize and has been divided into several different families over the years.

Important literature

Progel, A. 1868. Loganiaceae. In C.A.F. Martius (ed.) Flora brasiliensis 6(1): 251-300.

Zappi, D. 1989. Flora da Serra do Cipó, Minas Gerais: Loganiaceae. Bol. Bot. Univ. São Paulo 11: 85-97.

Zappi, D. 2005. Loganiaceae. In Wanderley, M.G.L., Shepherd, G.J., Mehlem, T.S. & Giulietti, A.M. (eds.) Flora Fanerogâmica do Estado de São Paulo 4: 261-271.

Zappi, D. 2006. Flora da Reserva Ducke, Amazonas, Brasil: Loganiaceae. Rodriguésia 57(2): 193-204.

How to cite

Zappi, D. (2009). Neotropical Loganiaceae. 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/Loganiaceae.htm.