One of the often brightly colored parts of a flower immediately surrounding the reproductive organs; a division of the corolla.
[New Latin petalum, from Greek petalon, leaf.]
petaled pet'aled or pet'alled adj.
petal
Dictionary:
pet·al (pĕt'l)  |
n.
| Architecture: petal |
One of the overlapping shingles or tiles in imbrication.
| Columbia Encyclopedia: petal |
petal, one of the four basic parts of a flower, next innermost organ from the sepal. The whorl of petals is known collectively as the corolla [Lat.,=little crown]. The number of petals is usually constant within groups (e.g., five in the rose family), as are the numbers of the other organs. Identification by number is, however, complicated by various factors; the petals may be fused, inconspicuous, or entirely absent, in which case their role as the showy part of the flower is sometimes supplanted by modified leaves, the bracts, as in the dogwood and poinsettia, or by modified stamens, as in the canna and the lady's-slipper. Selective breeding can produce petallike stamens (e.g., in cultivated roses and geraniums) and so-called double flowers, i.e., varieties with more than the normal number of petals. Petals are usually brightly colored and often secrete perfume and nectar (in nectaries at the base of the petal) that attract insects and birds needed for cross-pollination. When fertilization has taken place the petals usually drop off; however, in some flowers they persist (see everlasting). In general there are fewer petals and their fusion is greater as the evolutionary development increases. Radially symmetrical arrangement also gives way to bilateral symmetry or even asymmetry.
| Food & Culture Encyclopedia: Petal |
| Gardener's Dictionary: petal |
One of a series of flower parts, often brightly colored and sometimes patterned.
| Wikipedia: Petal |
For other uses, see Petal (disambiguation).
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A petal (from Ancient Greek petalon "leaf", "thin plate") is one member or part of the corolla of a flower. The corolla is the name for all of the petals of a flower; the inner perianth whorl, term used when this is not the same in appearance (color, shape) as the outermost whorl (the calyx) and is used to attract pollinators based on its bright color. It is the inner part of the perianth that comprises the sterile parts of a flower and consists of inner and outer tepals. These tepals are usually differentiated into petals and sepals. The term "tepal" is usually applied when the petals and sepals are similar in shape and color. In a "typical" flower the petals are showy and colored and surround the reproductive parts. The number of petals in a flower (see merosity) is indicative of the plant's classification: eudicots (the largest group of dicots) having typically four or five petals and monocots and magnoliids having three, or some multiple of three, petals.[1]
The genetics behind the formation of petals, in accordance with the ABC model of flower development, are that sepals, petals, stamens, and carpels are modified versions of each other. It seems that the mechanisms to form petals evolved a small number of times (perhaps only once), rather than evolving independently from stamens in a large number of plants.[2]
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Variation
There exists considerable variation in form of petals among the flowering plants. The petals can be united towards the base, forming a floral tube. In some flowers, the entire perianth forms a cup (called a calyx tube) surrounding the gynoecium, with the sepals, petals, and stamens attached to the rim of the cup.
The flowers of some species lack or have very much reduced petals. These are often referred to as apetalous. Examples of flowers with much reduced perianths are found among the grasses.
The petals are usually the most conspicuous parts of a flower, and the petal whorl or corolla may be either radially or bilaterally symmetrical. If all of the petals are essentially identical in size and shape, the flower is said to be regular or actinomorphic (meaning 'ray-formed'). Many flowers are symmetrical in only one plane (i.e., symmetry is bilateral) and are termed irregular or zygomorphic (meaning yoke- or pair-formed). In irregular flowers, other floral parts may be modified from the regular form, but the petals show the greatest deviation from radial symmetry. Examples of zygomorphic flowers may be seen in orchids and members of the pea family. The petal is the colorful, often showy part of a plant.
Similar structures
Some plants have petaloid stamens, in plants like Canna that have true petals and staminodes, the stamen (staminodes) are modified to look like large showy petals.
A number of plants have bracts that resemble petals for example in Bougainvillea and Cornus florida (flowering dogwood). Petal-like bracts are common features in some plant families like Euphorbiaceae.
In many plants of the aster family such as the sunflower, Helianthus annuus, the circumference of the flower head is composed of ray florets. Each ray floret is anatomically an individual flower with a single large petal.
Corolla
Corolla is the collective term for petals of a flower taken as a group within the calyx. Normally the corolla is the most conspicuous part of a flower and of a bright colour other than green. The concept of corolla description is widely used in botany as a primary determinant of vascular plant identification. Alternatively the corolla may be considered as the inner whorl of the perianth structure. The role of the corolla in plant evolution has been studied extensively since Darwin postulated a theory of the origin of elongated corollae.[3]
References
- ^ Soltis, Pamela S.; Douglas E. Soltis (2004). "The origin and diversification of angiosperms". American Journal of Botany 91: 1614–1626. doi:. http://www.amjbot.org/cgi/content/full/91/10/1614.
- ^ Rasmussen, D. A. (2008). "One size fits all? Molecular evidence for a commonly inherited petal identity program in Ranunculales". American Journal of Botany. doi:.
- ^ Analysis of theory of evolution of corolla elongation involving pollinating species
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| Translations: Petal |
Dansk (Danish)
n. - blomsterblad
Deutsch (German)
n. - Blütenblatt
Ελληνική (Greek)
n. - (φυτολ.) πέταλο, ανθόφυλλο
Português (Portuguese)
n. - pétala (f)
Svenska (Swedish)
n. - kronblad
中文（简体）(Chinese (Simplified))
花瓣
中文（繁體）(Chinese (Traditional))
n. - 花瓣
العربيه (Arabic)
(الاسم) بتله, تويجيه, ورقه تويجيه
עברית (Hebrew)
n. - עלה-כותרת (בפרח)
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 | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved. Read more |
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| Architecture. McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc. All rights reserved. Read more |
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| Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/. Read more |
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| Food & Culture Encyclopedia. Encyclopedia of Food and Culture. Copyright © 2003 by The Gale Group, Inc. All rights reserved. Read more |
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| Gardener's Dictionary. Taylor's Dictionary for Gardeners, by Frances Tenenbaum. Copyright © 1997 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved. Read more |
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| Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Petal". Read more |
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