Swollen portion of the petiole (or petiolule) involved in movement, usually positioned at the petiole base, but sometimes at the apex (Fig. 4.3).

The swollen base of a petiole or petiolule.

a thickening at the base of such leaflets where the turgor pressure can rapidly drop

a swelling at the base of the stalk of a leaf or leaflet, often glandular or responsive to touch.

swollen place at leaf or leaflet base.