noun
definition
Conspicuous bract, bract pair or ring of bracts at the base of an inflorescence.
Examples of involucre in a Sentence
The seeds, or properly fruits, are contained singly in a stony involucre or bract, which does not open until the enclosed seed germinates.
The young involucre surrounds the female flower and the stalk supporting the spike of male flowers, and when ripe has the appearance of bluish-white porcelain.
The filbert, 2 among the numerous varieties of Corylus Avellana, is extensively cultivated, especially in Kent, for the sake of its nuts, which are readily distinguished from cob-nuts by their ample involucre and greater length.
The cup-shaped involucre of Cornucopia is a dilatation of the axis into a hollow receptacle with a raised border.
The remarkable ovoid involucre of Coix, which becomes of stony hardness, white and polished (then known as " Job's tears," q.v.), is also a modified bract or leaf-sheath.
In Setaria and allied genera the spikelet is subtended by an involucre of bristles or spines which represent sterile branches of the inflorescence.
At the base of the general umbel in umbelliferous plants a whorl of bracts often exists, called a general involucre, and at the base of the smaller umbels or umbellules there is a similar leafy whorl called an involucel or partial involucre.
In Compositae the name involucre is applied to the bracts surrounding the head FIG.
This involucre is frequently composed of several rows of leaflets, which are either of the same or of different forms and lengths, and often lie over each other in an imbricated manner.
The leaves of the involucre are spiny in thistles and in teazel (Dipsacus), and hooked in burdock.
In Compositae besides the involucre there are frequently chaffy and setose bracts at the base of each flower, and in Dipsacaceae a membranous tube surrounds each flower.
In Cynosurus (Dog's tail) -- C the pectinate involucre which conceals the spikelet is a barren or abortive spikelet.