Flowers

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  • Topic: Flower, Pollen, Plant sexuality
  • Pages : 3 (1007 words )
  • Download(s) : 491
  • Published : April 6, 2013
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A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Magnoliophyta, also called angiosperms). The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs. Flowers may facilitate outcrossing (fusion of sperm and eggs from different individuals in a population) or allow selfing (fusion of sperm and egg from the same flower). Some flowers produce diaspores without fertilization (parthenocarpy). Flowers contain sporangia and are the site where gametophytes develop. Flowers give rise to fruit and seeds. Many flowers have evolved to be attractive to animals, so as to cause them to be vectors for the transfer of pollen. In addition to facilitating the reproduction of flowering plants, flowers have long been admired and used by humans to beautify their environment, and also as objects of romance, ritual, religion, medicine and as a source of food.

Floral formula

Floral diagram for the genus Nepenthes
A floral formula is a way to represent the structure of a flower using specific letters, numbers, and symbols. Typically, a general formula will be used to represent the flower structure of a plant family rather than a particular species. The following representations are used: Ca = calyx (sepal whorl; e. g. Ca5 = 5 sepals)

Co = corolla (petal whorl; e. g., Co3(x) = petals some multiple of three ) Z = add if zygomorphic (e. g., CoZ6 = zygomorphic with 6 petals) A = androecium (whorl of stamens; e. g., A∞ = many stamens) G = gynoecium (carpel or carpels; e. g., G1 = monocarpous)

x: to represent a "variable number"
∞: to represent "many"
A floral formula would appear something like this:
Ca5Co5A10 - ∞G1
Several additional symbols are sometimes used
Morphology

A stereotypical flower consists of four kinds of structures attached to the tip of a short stalk. Each of these kinds of parts is arranged in a whorl on the...
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