The petiole is a stalk that attaches a leaf to the plant stem. In petiolate leaves, the leaf stalk (petiole) may be long, as in the leaves of celery and rhubarb, short or completely absent, in which case the blade attaches directly to the stem and is said to be sessile. Subpetiolate leaves are nearly petiolate, or have an extremely short petiole, and may appear sessile.[2]:157 The broomrape family Orobanchaceae is an example of a family in which the leaves are always sessile.[3]:639 In some other plant groups, such as the speedwell genus Veronica, petiolate and sessile leaves may occur in different species.
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