A membranous envelope.
A whorl or rosette of bracts surrounding an inflorescence (especially a capitulum) or at the base of an umbel.‘The cupules are simple involucres of bracts which are spirally arranged (according to a Fibonacci pattern) on the floral axis preceding the flower.’
- ‘Basal leaves and flowers initiate from a tuberous rhizome and three green cauline leaves arranged in a whorl form an involucre around the developing flower.’
- ‘The Hermaphrodite cyathium shows the characteristics measured (length and width of the cyathium involucre and the nectary).’
- ‘We used to help my grandmother gather the flowers, remove the green involucre from beneath the flowerhead and separate the rays, or florets.’
- ‘All flowers are enclosed within an involucre with four marginal glands.’
Late 16th century from French, or from Latin involucrum, from involvere ‘roll in, envelop’ (see involve).