Term:

Ligule
Definition:

Ligules are strap-like structures that can arise from different structures; for example, the ligule of a species of Bromeliaceae arises from petals; whereas that of a grass arises at the juncture of the blade sheath and the leaf blade and the ligule of a flower of Lecythidaceae arises from fusion of stamens.
Notes:

A strap-shaped organ; e.g., the blade of the corolla of a ray flower of some Asteraceae; the thin projection from the apex of the leaf sheath such as that of the Cyperaceae, Poaceae, and Zingiberaceae; an outgrowth from the petal of some Bromeliaceae; an adaxial outgrowth of the corona of some Apocynaceae; an outgrowth of the staminal ring of a zygomorphic flowered Lecythidaceae; or an appendage of the column face important in the classification of Dichea in which the ligule is usually different in each species; lateral prolongation of the staminal ring in zygomorphic-flowered species of Lecythidaceae.