petiole

English[edit]

WOTD – 11 January 2012

Borrowed from French pétiole, and its source, Late Latin petiolus (“little foot”), diminutive form of Latin pēs (“foot”).

petiole (plural petioles)

(botany) The stalk of a leaf, attaching the blade to the stem.
Synonym: pedicel (stalk of a flower)
- 1978, Harry T. Valentine, Estimating Defoliation of Hardwoods Using Blade-petiole Relations, Forest Service Research Paper NE 405, US Department of Agriculture, page 1:
  Most insects consume tissue from the leaf blade were measured just past the twist on the side away only, leaving the leaf petioles unscathed.
- 1992, Karl J. Niklas, Plant Biomechanics‎^[1], University of Chicago Press, page 167:
  By contrast, the petioles of large pinnate leaves, as well as stems, typically resist torsion by placing stiff materials with high elastic moduli (like sclerenchyma) toward the perimeters of their cross sections.
- 2000, Mike Hansell, Bird Nests and Construction Behaviour‎^[2], Cambridge University Press, page 116:
  An example of this is leaf petioles. Some species of trees have pinnate leaves which, when the leaves fall, shed pinnae from the petiole, which is then left as a tapering, somewhat flexible rod.
(entomology, insect anatomy) A narrow or constricted segment of the body of an insect; especially, the metasomal segment of certain Hymenoptera, such as wasps.
Synonym: pedicel (used more generally, of arthropods)
(entomology) The stalk at the base of the nest of the paper wasp.

The presence of a petiole (narrow body segment) is the defining characteristic distinguishing the suborder Apocrita (ants, bees and wasps) from the rest of order Hymenoptera (i.e., from the paraphyletic suborder Symphyta).

stalk of a leaf