This MedLibrary.org supplementary page on Involucre is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
The calybium and the cupule make up the accessory fruit of flowering plants in the family Fagaceae. These two parts derive from different flower components.
The cupule holds and protects the seed during its growth and maturation. In some genera (e.g. Lithocarpus, Quercus), it only partly encloses the single nut, while in others (e.g. Castanea, Fagus), it fully encloses the two or more nuts, and splits open at maturity into four valves to release the nuts. It is derived from the vegetative part of the flower (its attachment to the rest of the plant).
The cupule is covered by numerous scales. In some (e.g. Castanea), the scales are developed into sharp spines, giving the nut protection from squirrels and other seed predators, while in others (e.g. most Quercus), they are not. In Lithocarpus, the cupule is very hard and bone-like in texture.
The calybium (plural: calybia) is the fruit proper. It develops from an inferior ovary, meaning it is initially encased in the future cupule. Technically the calybium is a nut, as its ovary wall becomes dry with the embryo loosely enclosed inside, and remaining closed until germination.
Involucre
The involucre corresponds to the cupule; it is found in the related family Betulaceae, notably in the genera Carpinus and Corylus. It differs in being more leafy in appearance, but performs a similar role in protecting the developing nuts. The term involucre is also used for a highly conspicuous bract, bract pair or ring of bracts at the base of an inflorescence.
References
- Gee, Carole T.; Sander, P. Martin & Petzelberger, Bianka E.M. (2003): A Miocene rodent nut cache in coastal dunes of the Lower Rhine Embayment, Germany. Palaeontology 46(6): 1133-1149. doi:10.1046/j.0031-0239.2003.00337.x
Wikipedia content modification information:
- This page was last modified on 23 November 2008, at 00:13.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Involucre".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.