Neotropical Hydnoraceae

Jon L.R. Every

University of Plymouth, U.K. 


Leafless, echlorophyllus, root-parasitic herbs; roots rhizome -like. Flowers from rooting body (frequently semi-subterranean), large, solitary, bisexual, regular, thick, fleshy, brownish, rugoes on outer surface, coloured on innder surface; tepals 3 - 4 , valvate, sepaloid, basally connate; stamens equal in number and opposite to perianth parts, staminodes 3, alternating with anthers, anthers connate forming a dome or cap with a small central opening; ovary inferior, syncarpous, unilocular, carpels 3-5, ovules numerous in three groups, stigma sessile. Fruit sweet-smelling, coriaceous berry, woody pericarp splitting irregularly. Seeds small and numerous (500 - 90,000).

Notes on delimitation

  • Currently placed within the Piperales alongside the aquatic Saururaceae, the Piperaceae Lactoridaceae - which are restricted to the Juan Fernandez Islands - and the family Aristolochiaceae (APGIII).

Distribution in the Neotropics

  • Semi-arid areas of Brazil, Paraguay, Costa Rica, Tropical Chile and Argentina.

Distinguishing characters (always present)

  • Root-parasitic herbs.
  • No chlorophyll present.
  • No leaves.
  • Bizarre large, thick, fleshy, valvate flowers which emerge from the ground.

Other important characters

  • Flower coloured brown on the outside and whitish inside.
  • Anthers form a strange-looking dome with a small opening at the top.
  • Huge amount of seeds.

Key differences from similar families

Characters lacking from Neotropical Hydnoraceae but present in similar-looking families;

Number of genera

  • One genus with four species: Prosopanche americana (R. Br.) Kuntze, P. costaricensis L. D. Gómez,  P. bonacinae Speg and P. caatingicola R. F. Machado & L.P.Queiroz.


  • Native.

General notes

  • Defined by Lytton J. Musselman as 'The strangest plant in the World!'.

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 161(3): 105-121.

Heywood, V.H. 2007. Hydnoraceae. In: V.H. Heywood, R.K. Brummitt, A. Culham and O. Seberg (eds.). P.169. Flowering Plant Families of the World. Royal Botanic Gardens, Kew.

Musselman, L.J. & Visser, L.J. 1986. The strangest plant in the World!. Veld and Flora 71: 109-111.

Musselman, L.J. 2004. Hydnoraceae. In: Smith, N., Mori, S.A., Henderson, A., Stevenson, D.W. and Heald, S.V. (eds.). Flowering Plants of the Neotropics. Pp. 187-188. The New York Botanical Garden, Princeton University Press, Princeton.

Nickrent, D. (accessed Nov 2010). Hydnoraceae. In: Parasitic Plants Connection website.

Nickrent D.L., Blarer A., Qiu Yin-Long, Soltis D.E., Soltis P.S., and Zanis M. 2002. Molecular data place Hydnoraceae with Aristolochiaceae. American Journal of Botany 89:1809-1817.

Stevens, P. F. 2008. Angiosperm Phylogeny Website. Version 9 onwards.

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

How to cite

Every, J.L.R. (2010). Neotropical Hydnoraceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics.