Peristome (botany)
The peristome ( Greek peri- um something and stóma mouth ) is a term that is often used in biology . In zoology it describes the area around the mouth, the mouth of an animal. In botany the term is used in a figurative sense. The tooth-shaped formations around the mouth of the capsule of deciduous mosses are called peristomes, as is the border around the opening of the trap leaves of some carnivorous plants .
Moss
A ring of tooth-like structures on the edge of the capsule mouth of deciduous mosses is also known as a peristome. The morphology of this formation plays a major role in the bryological classification within the moss system.
The peristome teeth are often very complex. For example, they can be forked, bent, or twisted. In many mosses they consist of two layers with different cell wall structures that swell to different degrees. As a result, when the air humidity changes , a curvature movement occurs, similar to a bimetal strip . The capsule can thus be partially closed or opened so that the spores are only gradually released in dry weather.
The number of peristome teeth is always a multiple of 4.
The peristome can also consist of two rows of teeth, the inner row (the "endostome") being much more delicate than the coarse outer row (the "exostome"). In this case one speaks of a “double peristome”. In such a case, the rows are often staggered. Only the outer row of peristomes is involved in the swelling movement.
Mycology
In mycology, the opening at the vertex of the spore sac ( endoperidia ) through which the spores escape (for example in the case of earth stars ) is also called a peristome. The peristome can be different and is an important determinant within the genus.
Individual evidence
- ↑ Ewald Gerhardt: Röhrlinge, Porlinge, Bauchpilze, hose mushrooms and others . In: mushrooms. Spectrum of nature, BLV intensive guide . tape 2 . BLV, Munich / Vienna / Zurich 1985, ISBN 3-405-12965-6 , p. 25 .