Neotropical Corsiaceae

Paul J.M. Maas & Hiltje Maas-van de Kamer

National Herbarium of the Netherlands (Wageningen branch), Wageningen, the Netherlands.

Description

Herbs, mycoheterotrophic ("saprophytic") with short, tuberous rootsLeaves alternate, 4-6, reduced to closed sheaths.  Flowers bisexual, zygomorphic, terminal, solitary; tepals 6, petaloid, the 3 inner ones and 2 of the outer ones filiform, the median outer one wider and standard-like, reflexed, with 2 rows of bullate structures; stamens 6, with short filaments, anthers dorsifixed, extrorse; ovary inferior, 1-locular, placentation parietal, ovules many, styles 3, each with a capitate stigmaFruits reflexed capsules, opening with 1 terminal triangular aperture.  Seeds many, dust-like.

Notes on delimitation

  • Recent research states that the position of the family is uncertain, but in the APG III (Stevens, 2008; APG III, 2009) it is placed in Liliales.
  • In the past the Corsiaceae have been included in the Burmanniaceae
  • Cronquist (1981) placed the family in the order Orchidales with the Orchidaceae and Geosiridaceae.  Takthtajan (2009) placed it in Burmanniales along with Burmanniaceae and Thismiaceae.

Distribution in the Neotropics

Worldwide the Corsiaceae comprise three genera and ca. 30 species, of which only one genus occurs in the Neotropics.

  • Arachnitis Phil. - (2 spp.) montane, moist forests of Peru and Bolivia to Patagonia in the South, at elevations of 0-2,500 m.

Distinguishing characters (always present)

  • Mycoheterotrophic ("saprophytic") herbs with scale-like leaves.
  • Flowers solitary, terminal, zygomorphic, tepals 6 (5 filiform and 1 large, standard-like, enclosing the other ones in bud).
  • Fruit a capsule, opening with 1 terminal, triangular aperture.

Key differences from similar families

  • Corsiaceae can, when superficially studied, only be confused with Orchidaceae, but they clearly differ in having 6 stamens instead of  the 1, rarely 3, found in the Orchidaceae.

Status

  • Arachnitis is native in the Neotropics, and not cultivated.

General notes

  • Corsiaceae is a family rarely collected in the Neotropics, most collections come from extra-neotropical regions in Bolivia and Argentina.
  • Arachnitis species may be pollinated by fungus gnats (Ibisch et al., 1996).

Important literature

A.P.G. III. 2009. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III. Bot. J. Linnean Soc. 161: 105-121.

Cronquist, A. 1981. An integrated system of classification of flowering plants. Columbia University Press. New York

Henderson, A. & Stevenson, D.W. 2004. Corsiaceae. In: Smith, N., Mori, S.A., Henderson, A., Stevenson, D.W. and Heald, S.V. (eds.). Flowering Plants of the Neotropics, p. 429. The New York Botanical Garden, Princeton University Press, Princeton.

Ibisch, P.L., Neinhuis, C. and Rojas N., P.  1996. On the biology, biogeography, and taxonomy of Arachnitis Phil. nom. cons. (Corsiacae) in respect to a new record from Bolivia. Willdenowia 26: 321-332.

Maas, P.J.M. & Westra, L.Y.Th. 2005. Neotropical Plant Families. A concise guide of vascular plants in the Neotropics. 3rd ed., p. 70-71. A.R.G. Gantner Verlag K.G., Ruggell.

Neinhuis, C. & Ibisch, P.L. 1998. Corsiaceae. In: Kubitzki, K. (ed.). The Families and Genera of Vascular plants vol. III, Vol. 3. Flowering Plants -Monocotyledons. Lilianae (except Orchidaceae), pp. 198-201. Springer-Verlag, Berlin.

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

Takhtajan, A. 1997. Flowering Plants. 2nd ed. Springer-Verlag, Berlin.

How to cite

Maas, P.J.M. & Maas-van de Kamer, H. (2012). Neotropical Corsiaceae. 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/Corsiaceae.htm.