Sessility (botany)
Image:Trillium cernuum 1-eheep.jpg|thumb|The perennial wildflower Trillium cernuum possesses three leaves that are sessile at the top of the stem.
In botany, sessility is a characteristic of plant organs such as flowers or leaves that have no stalk. Plant parts can also be described as subsessile, that is, not completely sessile.
A sessile flower is one that lacks a pedicel. A flower that is not sessile is pedicellate. For example, the genus Trillium is partitioned into multiple subgenera, the sessile-flowered trilliums and the pedicellate-flowered trilliums.
The term "sessility" is also used in mycology to describe a fungal fruit body that is attached to or seated directly on the surface of the substrate, lacking a supporting stipe or pedicel.