In botany, with the term ligula, in botany, various anatomical structures present in plants are indicated.
The ligule is a scary or membranous appendix with which, in the leaves of the Poaceae, the sheath that wraps the culm continues for a short distance beyond the point of insertion of the lamina.
In these plants the ligule can be:
– membranous, and therefore very evident;
– only a fringe of hair;
The leaves of the selaginellae and of the Isoëtes are also provided with ligula.
Furthermore, the type of flower of the Asteraceae takes the term of ligula (or ligulate flower or tongue flower), together or not with the tubular flowers on the same flower head. This flower is characterized by a corolla open on one side lengthwise almost to the base and flattened, similar to a tongue.
The marginal ornamentation of the frustule of the Diatoms is also so called, forming a small sharp or rounded tooth.