Flower formula

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The flower formula is a meaningful representation of the flower structure . The flower structure of a species , genus or family is represented by symbols. As with a flower diagram , in addition to the actual circumstances, interpretations such as the loss of organs, secondary reproductions, etc. can also be shown here.

Structure of the flower formula

It is preceded by a symbol that reflects the symmetry of the flower:

  • A star or for a radial symmetry flower ( actinomorphic )
  • A down arrow for a (median), a left arrow for a (transverse) and an oblique left arrow for a (crooked) zygomorphic flower with only one axis of symmetry.
  • A spiral Screwed PNGor Spiral - floral formulae.svgfor a screwy flower structure
  • A straight cross Dissymmetrical.pngor a frame symbol ┼ for a disymmetrical flower with two mutually perpendicular axes of symmetry (actinomorphic)
  • A flash of lightning Asymmetrical.pngor ↯ for an asymmetrical bloom

The flower organs are listed as letters from the outside in or from the bottom up along the flower axis :

In the case of an inflorescence that is not divided into calyx and crown

Or with a double flower envelope, which is divided into a calyx and a crown

  • = Calyx , the chalice, raised for a sepaloid organ
  • = Corolla , the corolla, raised for a petaloid organ

Identical again for both

In addition to the above capital letters, there are subscripts or superscripts as well as normal additional information:

  • A number that indicates the number of links. For example stands for three sepals. If the number of the respective flower organs is indefinite (there are flowers with different numbers of, for example, sepals), or if the number of flower organs exceeds 10-12, the mathematical symbol for infinity is used .
  • Standing at farmers time flowers bloom elements such. B. stamens or petals, tepals in several circles, each circle of petals is considered separately and this is indicated by a plus + . thus means that there are 2 circles with 5 stamens each. A semicolon - indicates the number of organs, i.e. from to. If you want to specify “or” and “rarely”, this is best written out.
  • Reductions; with a superscript r , or losses in individual organs are placed after the number, for example in the case of staminodes . Completely reduced parts are marked with a degree symbol ° or a superscript zero and the theoretical number z. B. ° or the real number 0 is written. Often the missing organ circle is also left out in the flower formula for the sake of simplicity.
  • Adhesions of one (X) or consecutive whorls, two [X] and three {X}, are shown in different brackets. For example, stands for three fused carpels, means that the 5 petals are fused with each other and also the corolla with the stamens.
    • When the upper and lower lips are formed, the number of leaves that have come together to form the upper lip is put in the numerator, and those of the lower lip in the denominator of a fraction; so z. B. or is also possible . A break separates morphologically contradicting organs within an organ. Also z. B. with butterfly flowers flag, wings and boat . You can also find the use of a comma instead of a fraction, so .
    • If the adhesions are basal or apical, the bracket can be placed low or high z. B. for disc flowers here denotes a stamen- corolla tube and synanthic stamens.

Just in ovary also applies:

  • A dash above, below or in the middle indicates the position of the ovary . Examples are or for subordinate and or for upper and semi-subordinate - - or -, as well as for middle without a dash or or .
    • It is also the ovules or and the chambers of the ovary, and the placentation and the number and position of the stylus further the scar and the number and direction of opening the pollen sacs are given, or Antherode (sterile anther), but this is only a few authors used.
  • A vertical line marks a separation by additional false partitions , real partitions can be designated with two vertical lines.


  • In the case of dioecious, separate-sexed flowers ( diocesan ), Androeceum and Gynoeceum are separated by a double slash or are marked with a preceding gender symbol. You can indicate female ♀ and male ♂ and hermaphrodite ☿ flowers, using symbols or the name in abbreviated form.
  • Front and cover sheets or bracts can also be indicated with and and an outer calyx with or .
  • Pistillode (sterile pistil) and Staminodien (sterile stamens) can also be designated, and a neutral flower can also be specified. Reduced organs can also be specified in an undefined manner.
  • Special cases such as androgynophore or gynophore and gynostemium , gynostegium etc. are best written in abbreviated form or in full, e.g. B. , or .
  • The resupination of a flower can also be noted with ®.
  • The arrangement and formation of the stamens can also be specified; synandrisch, monadelphisch etc., and the position in relation to the petals or sepals, so z. B. epipetal or -sepal, obdiplostemon etc. Here you can use the semicircular arrow counterclockwise above, a left-right arrow or a line to relate the organs, e.g. B. for epitepal stamens or and .
    • Honey leaves (petal-like stamens) can be indicated with or with for petaloid stamens.
    • Bundled stamens can with ; stands for the number of bundles, and tubular, monadelphic fused ones can also be specified.
  • Organ groups can also be specified by the group number and the superscript of the number in an instance, e.g. B. for 4 groups of 2 fused stamens. One also finds the use of a mark "×" instead of superscript, ie .
  • Special cases such as nectaries , secondary crowns , cyathia , calyptras etc. can be added at the end, e.g. B. , or .
  • "Semi-fertile" organs can be designated with a superscript and a half after the number ( ), as in the genus flower tube ; so .
  • The type of fruit or something else can also be specified at the very end. B. specify whether the flowers are protandric or protogynous etc.
  • Glumes and lodiculae are special in sweet grasses , they can each be referred to in abbreviated form.

Table with some examples

Flower formulas of some families of flowering plants
family Flower formula
Carnation family (Caryophyllaceae) or
Mint family (Lamiaceae)
Umbelliferae (Apiaceae)
Cruciferous family (Brassicaceae) Dissymmetrical.png
Lily family (Liliaceae) and rush family (Juncaceae)
Sedge family (Cyperaceae) or
Willow family (Salicaceae) or ♂ ::


Individual evidence

  1. Louis P. Ronse De Craene, A. Iwamoto, K. Bull-Hereñu, J. Farrar: Understanding the structure of flowers — The wonderful tool of floral formulas: A response to Prenner & al. In: Taxon. 63 (5), 2014, pp. 1103–1111, doi: 10.12705 / 635.35 , online at researchgate.net.
  2. ^ Matthias Baltisberger: Systematic Botany. 3., corr. Edition. vdf, 2009, ISBN 978-3-7281-3192-8 , p. 78.
  3. Exercises on the biology and systematics of native plants (PDF), on Bernhard Schnepf's website, accessed on July 29, 2018.