Sessility (botany)

For other uses, see Sessility (disambiguation).

In botany, sessility (meaning "sitting", in the sense of "resting on the surface") is a characteristic of plant organs such as flowers or leaves that have no stalk.^[1][2] Plant parts can also be described as subsessile, that is, not completely sessile.

The perennial wildflower Trillium cernuum possesses three leaves that are sessile at the top of the stem.

A sessile flower is one that lacks a pedicel (flower stalk). A flower that is not sessile is pedicellate. For example, the genus Trillium is partitioned into multiple subgenera, the sessile-flowered trilliums (Trillium subgen. Sessilia) 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.^[3]