Neotropical Gunneraceae

Livia Wanntorp

Swedish Museum of Natural History, Stockholm. 

Description

Perennial (except for one annual species, G. herteri Osten) herbs with stout pachycaulous rhizomatous stems surrounded by long-petioled leaves reaching up to 3 m in diameter in some species of the Neotropics. Stems provided with specialized organs, ontogenetically related to root primordia, that host Nostoc cells forming an endosymbiosis with Gunnera L. These organs covered by leaf-like scales of different sizes and shapes (except for G. herteri). Flowers small and dimerous, grouped in compound or simple racemes. Fruit drupaceous, green or red.

Notes on delimitation

  • Gunneraceae is considered as sister to the remaining core Eudicots according to recent molecular phylogenetic studies (e.g. Soltis et al. 2003).

Distribution in the Neotropics

  • Gunnera is present in Bolivia, Brazil, Central America, Mexico, Colombia, Ecuador, Peru, Argentina, Chile and Venezuela.

Distinguishing characters (always present)

  • Endosymbiosis with the cyanobacteria of the genus Nostoc.

Other important characters

  • Perennial herbs.
  • Stout pachycaulous rhizomapus stems surrounded by large leaves.
  • Specialized organs on the stems host cyanobacteria of teh genus Nostoc. These organs are covered by leaf-like scales.
  • Flowers simple, dimerous and grouped in pseudoterminal racemes.
  • Drupaceous fruits.

Number of genera

  • 1 Gunnera- 38 species in the Neotropics.

Status

  • Native.

Important literature

Schindler, A. K. 1905. Halorrhagaceae. In Engler, A. (ed.) Das Pflanzenreich IV, 225. Leipzig: W. Engelmann, pp 1-133.

Skottsberg, C. 1928. Zur organographies von Gunnera. Svensk Bot. Tidskrift 22: 392-415.

How to cite

Livia Wanntorp (2009). Neotropical Gunneraceae. 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/Gunneraceae.htm.