pulvinus

American  

[puhl-vahy-nuhs] / pʌlˈvaɪ nəs /

noun

plural

pulvini

1. Botany. a cushionlike swelling at the base of a leaf or leaflet, at the point of junction with the axis.

2. Architecture. pulvinar.

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pulvinus British  

/ pʌlˈvaɪnəs /

noun

1. a swelling at the base of a leafstalk: changes in its turgor pressure cause changes in the position of the leaf

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Etymology

Origin of pulvinus

First recorded in 1855–60, pulvinus is from the Latin word pulvīnus cushion

Example Sentences

The petiole was secured so that the basal joint, or pulvinus, of one of the lateral leaflets was at the centre of a graduated arc placed close behind the leaflet.

From The Power of Movement in Plants by Darwin, Charles

At the base of the peduncle there is a mass of small cells, forming a well-developed pulvinus, which is exteriorly coloured purple and hairy.

From The Power of Movement in Plants by Darwin, Charles

These movements, when a pulvinus is present, are often complicated by the rotation of the leaf or leaflet; and such rotation on a small scale occurs during ordinary circumnutation.

From The Power of Movement in Plants by Darwin, Charles

The movements of pulvinated cotyledons are generally larger in extent than those without a pulvinus; nevertheless some of the latter moved through an angle of 90o.

From The Power of Movement in Plants by Darwin, Charles

The seat of both the twisting and bending movement is in the pulvinus of the sub-petioles.

From The Power of Movement in Plants by Darwin, Charles