Floral formula
✶ K5 [C(5) A5] G(5) | |
Floral formula of Anagallis arvensis.[1]: 307 Polysymmetric flower. The perianth consists of 5 free sepals and 5 joined petals, which are fused with androecium. Flower is bisexual, it contains 5 stamens, pistil is fused of five carpels, ovary is superior. |
A floral formula is a
A floral formula is often used along with a floral diagram.
History
Floral formulae were developed at the beginning of the 19th century.[2] The first authors using them were Cassel[3] (1820) who first devised lists of integers to denote numbers of parts in named whorls; and Martius[4] (1828). Grisebach[5] (1854) used 4-integer series to represent the 4 whorls of floral parts in his textbook to describe characteristics of floral families, stating numbers of different organs separated by commas and highlighting fusion. Sachs[6] (1873) used them together with floral diagrams, he noted their advantage of being composed of "ordinary typeface".
Although
partially utilized their way of writing the formulae in his book Floral Diagrams.Contained information
Organ numbers and fusion
The formula expresses counts of different floral organs;[note 1] these are usually preceded by letters or abbreviations according to the organ type. They are ordered corresponding to the arrangement of the parts of the flower from the outside to the inside:
Bracts | Bracteoles |
Tepals (perigon or perianth), or sepals (calyx) and petals (corolla) | Stamens (androecium) | Carpels (gynoecium) |
Ovules | |
---|---|---|---|---|---|---|
B[2] | Bt[2] | P[2] or CaCo[12] | A | G | V[2] or O[9] | |
K[2] or Ca[12] | C[2] or Co[12] |
The labels with darker backgrounds are less common. "V" used by Prenner et al. for the number of ovules per gynoecium is followed by lowercase letter describing the type of
The numbers are inserted after the labels, they may be formatted as sub- or superscript. If an organ is absent, its number is written as "0" or it is omitted, if there are "many" (usually more than 10–12) instances, it can be written as "∞". Whorls of the same organ are separated by "+". Organ counts within a whorl can be separated by ":", for example when part of the whorl is morphologically different. A range can be given if the number is variable, e.g. when the formula summarizes a taxon.
- K3+3 – a calyx with six free sepals, arranged as two separate whorls
- A∞ – many stamens
- P3–12 – perianth from three to twelve petals
Groups of organs can be described by writing the number of instances in the group as superscript.
- A5² – 5 groups of 2 stamens
The formula can also express organ fusion. Fusion of one organ type can be shown by enclosing the number in a circle, fusion of different organs can be represented by
- A(5) – five fused stamens
- [C(5) A5] – corolla fused from 5 petals, fused to stamens
Prenner et al. propose superscript zero for a lost organ, and superscript "r" for a reduced one. Ronse De Craene uses a
- A3:2r+50 – (Prenner et al.) androecium in two whorls, first contains 3 stamens and 2 staminodes, second whorl lost
- A1+2° – (Ronse De Craene) androecium in two whorls, first whorl containing a stamen, second whorl containing two stamens in Ovary position
Ovary position is shown by alternating the "G" label. Simpson circumvents the intricate formatting by expressing the ovary position by words.
superior ovary | inferior ovary | half-inferior ovary | |
---|---|---|---|
Prenner et al.,[2]: 243 Ronse De Craene[1]: 39 | G | Ĝ, Ğ | -G- |
Sattler[9]: xviii | G | ||
Simpson[11] | G…, superior | G…, inferior | G…, half-inferior |
Symmetry
Symmetry or arrangement may be described for the whole flower; in such case the corresponding symbol is usually placed at the beginning of the formula. It may be also outlined separately for different organs, placing it after their labels or numbers, or it may not be included in the formula at all. It is described by following symbols:
polysymmetry (actinomorphic) |
disymmetry | monosymmetry (zygomorphic) |
asymmetry | spiral arrangement | |
---|---|---|---|---|---|
Prenner et al.[2]: 242 | * | ┼ | ↓, → or Ø, depending on the symmetry plane orientation | ∂ | not mentioned |
Ronse De Craene[1]: 39 | ✶ | ↔ | ↓, arrow orientation depending on symmetry plane orientation | ↯ | ↺ |
Sattler[2]: xviii | ✳ | + | ∙|∙ | not mentioned | |
Judd et al.[10]: 66 | * | not mentioned | X | $ | |
Subrahmanyam[13] | ⊕ | % in median plane, ÷ in lateral plane | not mentioned | ||
Rosypal[14] | ✳ | ⤧ | ↓ | ↯ |
Sexuality
Sexuality of the flower can be highlighted by ☿ or ⚥ for hermaphrodite (bisexual), ♂ for male (staminate) and ♀ for female (pistillate) flower. The symbols are usually placed at the beginning of the formula, after or before the symmetry symbol. Prenner et al. recommend to use the corresponding symbols (♀ and ♂) only for flowers of separate sexuality. Ronse De Craene utilizes the words "pistillate" or "staminate" instead of the symbols.
Floral formula can also incorporate the fruit type, Judd et al.[10] place it at the very end.
Examples
↯ K3 [C3 A1°–3°+½:2°] Ğ(3)[1]: 39 – the formula of Canna indica; asymmetric flower; calyx of three free sepals; corolla of three free petals joined with androecium; androecium in two whorls, the outer whorl contains 1–3 staminodes, the inner contains ½ of a stamen and 2 staminodes; gynoecium fused of 3 carpels, inferior ovary
B BtC K3:(2)C↓ C3:2r↓ A(3):2r↓+4r:10 G1↓ Vm8–10
Using boxes
Narcissus Floral formula | |
Br ✶ ☿ P3+3+Corolla A3+3 G(3)
Bracteate, Actinomorphic, Bisexual Perianth: 6 tepals in 2 whorls of 3 Stamens: 2 whorls of 3 Ovary: Superior - 3 fused carpels |
Haloragaceae Floral formula | |
✶ or 3-4 free sepals, 3-4 free petals (or absent), 2-8 stamens, inferior ovary with 2-4 fused carpels |
See also
Notes
- ^ Bracts and bracteoles are not considered parts of the flower itself, yet they may be included in the floral formula
References
- ^ a b c d e f
Ronse De Craene, Louis P. (2010-02-04). Floral Diagrams: An Aid to Understanding Flower Morphology and Evolution. Cambridge: Cambridge University Press. ISBN 978-0-521-49346-8.
- ^ ISSN 0040-0262. Archived from the originalon 2018-03-29. Retrieved 2014-02-06.
- ^ Cassel, F. P. (1820). Morphonomia botanica: sive observationes circa proportionem et evolutionem partium plantarum. Colonia Agrippina [Cologne]: M. DuMont-Schauberg.
- ^ Martius, C. F. (1828). "Über die Architectonik der Blüthen". Isis (Oken) (21): 522–529.
- ^ Grisebach, A. (1854). Grundriss der systematischen Botanik. Göttingen: Verlag der Dieterichschen Buchhandlung.
- ^ Sachs, J. (1873). Lehrbuch der Botanik nach dem gegenwaertigen Stand der Wissenschaft. Leipzig: Engelmann.
- ^ Eichler, August Wilhelm (1875). Blüthendiagramme, erster Theil: Enthaltend Einleitung, Gymnospermen, Monocotylen und sympetale Dicotylen. Vol. 1. Leipzig: Wilhelm Engelmann.
- ^ Eichler, August Wilhelm (1878). Blüthendiagramme, zweiter Theil: Enthaltend die apetalen und choripetalen Dicotylen. Vol. 2. Leipzig: Wilhelm Engelmann.
- ^ a b c
Sattler, Rolf (1973). Organogenesis of flowers; a photographic text-atlas. Toronto, Buffalo: University of Toronto Press. ISBN 0-8020-1864-5.
- ^ a b c
Judd, Walter S.; Christopher S. Campbell; ISBN 0878934030.
- ^ a b
Simpson, Michael George (2010). Plant Systematics. Oxford (Great Britain): Academic Press. ISBN 978-0-12-374380-0.
- ^ a b c "Floral formula".
- ^
Subrahmanyam, N. S. (1997-01-01). Modern Plant Taxonomy. Jangpura, New Delhi: South Asia Books. ISBN 9780706993462.
- ^
Rosypal, Stanislav (2003). Nový přehled biologie. Praha: Scientia. ISBN 80-7183-268-5.
Bibliography
External links
- Kvetné vzorce – a website dedicated to floral formulae (in Slovakian)
- Table 2.1. Floral formulae; symbols used in this book. In Ronse De Craene, p. 39
- Symbols employed in floral formula. In Subrahmanyam, p. 42
- Floral Diagram Generator – a website to generate floral diagrams from floral formulae.