Merosity (from the greek méros, which means having parts) refers to the number of component parts in a distinct whorl of a plant structure.
The term is most commonly used in the context of a flower where it refers to the number of sepals in a whorl of the calyx, the number of petals in a whorl of the corolla, the number of stamens in a whorl of the androecium, or the number of carpels in a whorl of the gynoecium. The term may also be used to refer to the number of leaves in a leaf whorl.
Noun | Adjective | |
---|---|---|
2 parts | dimery | dimerous, 2-merous |
3 parts | trimery | trimerous, 3-merous |
4 parts | tetramery | tetramerous, 4-merous |
5 parts | pentamery | pentamerous, 5-merous |
many parts | polymery | polymerous |
few parts | oligomery | oligomerous |
The adjective n-merous refers to a whorl of n parts, where n is any integer greater than one.
In nature, five or three parts per whorl have the highest frequency of occurrence, but four or two parts per whorl are not uncommon. Two consecutive whorls of dimerous petals are often mistaken for tetramerous petals.
If all of the whorls in a given floral arrangement have the same merosity, the flower is said to be isomerous, otherwise the flower is anisomerous. For example, Trillium is isomerous since all whorls are trimerous (one whorl of three sepals, zero or one whorl of three petals, two whorls of three stamens each, and one whorl of three carpels). Trillium also has one whorl of three leaves.
Noun | Adjective | |
---|---|---|
equal parts | isomery | isomerous |
unequal parts | anisomery | anisomerous |
This article uses material from the Wikipedia English article Merosity, which is released under the Creative Commons Attribution-ShareAlike 3.0 license ("CC BY-SA 3.0"); additional terms may apply (view authors). Content is available under CC BY-SA 4.0 unless otherwise noted. Images, videos and audio are available under their respective licenses.
®Wikipedia is a registered trademark of the Wiki Foundation, Inc. Wiki English (DUHOCTRUNGQUOC.VN) is an independent company and has no affiliation with Wiki Foundation.