Neotropical Cuscutaceae

Jon L.R. Every

University of Plymouth, U.K. 

Description

Herbaceous, stem-twining parasitic vines; root system very short lived; stem filiform, yellow, red or orange in colour. Leaves reduced, spirally arranged, simple, sessile, scale-like, glabrous, mostly achlorophyllous; extra-floral nectaries sometimes present. Inflorescence axillary, cymose,  spicate or in heads. Flowers regularly symmetrical, bisexual, bracteate or not, disk present; sepals 3-5, imbricate, persistent; petals 3-5, imbricate, gamopetalous; corona fimbriate, alternating with stamens; stamens 5(-10), adnate to and alternating with the petals; anthers adnately fixed or +/- versatile, dehiscing by full-length longitudinal slits; ovary superior, syncarpous, carpels 2, locules (1-)2(-4), styles 1-3, separate to connate. Fruit a long-beaked capsule (rarely indehiscent). Seeds 1-6, embryo coiled, acotyledonous.

Notes on delimitation

  • Commonly included as one of the twelve sub -families of the Convolvulaceae, including in the most recent angiosperm classification undertaken by the Angiosperm Phylogeny Group (APGIII, 2009).

Distribution in the Neotropics

  • Can be found throughout the Neotropics growing in mesophytic habitats - particularly along streams and in areas associated with anthropogenic ecosystems. Occasionally found in halophytic areas (Cuscuta salina Engelmann).

Distinguishing characters (always present)

Key differences from similar families

  • Differs from Convolvulaceae in that Cuscuta L. is often chlorophyll-lacking and parastic, has a withering terrestrial root system which is short-lived, and no internal phloem.
  • Has similarities with species of the genus Cassytha Miller of Lauraceae, such as its parasitic tendencies, but can be distinguished by Cassytha's greater numbers of floral parts.

Number of genera

  • One: Cuscuta, with approximately 50 species.

Status

  • Native and introduced via shipments of commercial seed.

General notes

  • Also known as Dodder and Devil's Guts, members of the Cuscutaceae are regarded as some of the worst weeds in the world. Attaching to their agricultural hosts through haustoria and twining around their victims they steal light and nutrients from valuable crops.

Important literature

Costea, M. 2007 onwards. Digital Atlas of Cuscuta. http://www.wlu.ca/page.php?grp_id2147&p=8968

Heide-Jørgensen, H.S. 2008. Parasitic Flowering Plants. 438 pp. Brill, Leiden.

Kuijt, J. 1969. The Biology of Parasitic Flowering Plants. 246 pp. University of California Press, Berkeley, California.

Maas, P. J. M. & Westra, L. Y. Th. 2005. Convolvulaceae. 358 pp. Neotropical Plant Families. 3rd ed.

Musselman, L.J. 2004.  Cuscutaceae. In: Smith, N., Mori, S.A., Henderson, A., Stevenson, D.W. and Heald, S. . (eds.). Flowering Plants of the Neotropics. Pp. 124-5. The New York Botanical Garden, Princeton University Press, Princeton.

Nickrent, D.L. 1998-onwards. The Parasitic Plant Connection. http://www.parasiticplants.siu.edu/.

Staples, G.W. & Brummitt, R.K. 2007. Convolvulaceae. In: Heywood, V.H., Brummitt, R.K., Culham, A. & Seberg, O. (eds.). Flowering Plant Families of the World. Pp 108 - 110. Royal Botanic Gardens, Kew.

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

Yunker, T.G. 1932. The genus Cuscuta. Mem.Torrey bot. Club 18: 113-331.

Yunker, T.G. 1965. Cuscuta. N. Amer. Fl., ser. 2, 4: 1-51.

How to cite

Every, J.L.R. (2010). Neotropical Cuscutaceae. 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/Cuscutaceae.htm.