Definition

Noun: 1. A whorl or ring of bracts surrounding or subtending a flower cluster or a single flower: In botany, an involucre is a structure composed of one or more whorls of small, leaf-like bracts. These bracts are located at the very base of an inflorescence (a group of flowers) or, less commonly, at the base of a single flower. Its primary function is often protective, shielding the developing flower buds.

Examples of Usage

• Noun:
  • The bright green involucre at the base of the dandelion head is a key identifying feature.
  • Botanists examined the involucre to help classify the species of the wildflower.
  • In plants like members of the carrot family (Apiaceae), the involucre is found at the base of the entire compound umbel.

Advanced Usage

• Involucral (adjective): Pertaining to, resembling, or having the nature of an involucre.
  • The involucral bracts were covered in fine hairs.

Variants and Related Words

• Involucel (noun): A secondary involucre; a small involucre surrounding part of a compound inflorescence, such as the base of a single umbellet within a larger umbel.
• Involucrum (noun): This is a Latin-derived synonym for involucre, though in modern botanical English, "involucre" is the standard term. (Note: In anatomy and medicine, "involucrum" has a different meaning, referring to a sheath of new bone growth).

Synonyms

• Bract collar: A descriptive, non-technical synonym emphasizing the ring-like arrangement.
• Phyllary: A specific term for a bract in the involucre of a flower head in the aster family (Asteraceae).

Related Terms (Contextual)

• Bract: A modified leaf associated with a flower or inflorescence. An involucre is composed of bracts.
• Inflorescence: The complete flower head of a plant including stems, stalks, bracts, and flowers. The involucre is found at its base.
• Calyx: The outermost whorl of a flower, composed of sepals. It is important to distinguish the involucre (made of bracts, below the flower) from the calyx (made of sepals, part of the flower itself).

Noun

1. a highly conspicuous bract or bract pair or ring of bracts at the base of an inflorescence