Sessility (botany)

For other uses, see Sessility (disambiguation).

In botany, sessility (meaning "sitting", used in the sense of "resting on the surface") is a characteristic of plant parts (such as flowers and 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.

Sessile leaves lack petioles (leaf stalks). A leaf that is not sessile is petiolate. For example, the leaves of most monocotyledons lack petioles.^{[citation needed]}

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]

References

1. Beentje, H.; Williamson, J. (2010). The Kew Plant Glossary: an Illustrated Dictionary of Plant Terms. Royal Botanic Gardens, Kew: Kew Publishing.
2. Hickey, M.; King, C. (2001). The Cambridge Illustrated Glossary of Botanical Terms. Cambridge University Press.
3. Ulloa, Miguel; Halin, Richard T. (2012). Illustrated Dictionary of Mycology (2nd ed.). St. Paul, Minnesota: The American Phytopathological Society. p. 575. ISBN 978-0-89054-400-6.