Question

What's pulvinus

Answer 1

An enlarged area at the base of a petiole, at a node, or at the base of a panicled branch, producing movement by growth or swelling is known as pulvinus.
They consist of a core of vascular tissue within a flexible, bulky cylinder of thin-walled parenchyma cells. A pulvinus is also sometimes called a geniculum.
Pulvinus takes the pressure / force and bends elastically when force is applied. Pulvinus is responsible for the change in the orientation or position of the leaf. Pulvinus changes its orientation by losing water in it or by gaining water.
Pulvinus also enables folding of leaf when some one or something touches the leaves, in some plants.Eg. toch-me-not plant