 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 have an extremely short petiole, and may appear sessile.The broomrape family Orobanchaceae is an example of a family in which the leaves are always sessile.