• synonyms


  1. Botany. a collection or rosette of bracts subtending a flower cluster, umbel, or the like.
  2. a covering, especially a membranous one.
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Origin of involucre

1570–80; < Middle French < Latin involūcrum involucrum
Related formsin·vo·lu·cral, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for involucre

Historical Examples

  • Large umbel of yellow flowers, no involucre and no involucels.

    The Medicinal Plants of the Philippines

    T. H. Pardo de Tavera

  • The involucre is simple and leafy, and the receptacle is conical.

  • Plants with heads of florets on a common receptacle, surrounded by an involucre.

  • The sporangia are comparatively scanty, and are fully covered by the involucre.

    Beautiful Ferns

    Daniel Cady Eaton

  • Spikelets in our species umbelled, and the involucre 2–3-leaved.

British Dictionary definitions for involucre


involucrum (ˌɪnvəˈluːkrəm)

noun plural -cres or -cra (-krə)
  1. a ring of bracts at the base of an inflorescence in such plants as the composites
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Derived Formsinvolucral, adjectiveinvolucrate, adjective

Word Origin

C16 (in the sense: envelope): from New Latin involucrum, from Latin: wrapper, from involvere to wrap; see involve
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

involucre in Science


  1. A series of bracts beneath or around a flower or flower cluster. The cupule, the cuplike structure holding an oak acorn, is a modified, woody involucre.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.