Flower Formula
A flower formula is a short-hand method for describing a flower using letters,
numbers and symbols to represent the flower parts. There is no single,
standard notation, but they can be useful in visualizing the parts of a flower.
Typical flower formula =
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K(5) [ C 5 A 5 ] G(2)
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Flower Formula
The first symbol indicates flower symmetry. Actinomorphic flowers
have radial symmetry, while Zygomorphyic flowers lack radial
symmetry and can be divided only along one plane.
K(5) [ C 5 A 5 ] G(2)
= Actinomorphic
= Zygomorphic
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Flower Formula
The next set of letters represent the organ in each flower whorl and the
numbers after the letter is the number of organs in the whorl (i.e. 5 petals).
K(5) [ C 5 A 5 ] G(2)
= Actinomorphic
= Zygomorphic
K = Calyx
C = Corolla
P = Tepals
A = Androecium
G = Gynoecium
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Flower Formula
In some systems, BR is included to
indicate the presence of bracts.
Br
K(5) [ C 5 A 5 ] G(2)
= Actinomorphic
= Zygomorphic
K = Calyx
C = Corolla
P = Tepals
A = Androecium
G = Gynoecium
Br = Bracts
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Flower Formula
In some systems, BR is included to
indicate the presence of bracts.
In others, the symbols for male, female
or a perfect flower is also included.
Female
Male
Br
Perfect
K(5) [ C 5 A 5 ] G(2)
K(5) [ C 5 A 5 ] G(2)
= Actinomorphic
= Zygomorphic
K = Calyx
C = Corolla
P = Tepals
A = Androecium
G = Gynoecium
Br = Bracts
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Parentheses ( ) indicate if the organs within a whorl are united or fused
(i.e. united sepals) and brackets [ ] indicate if organs are united between
whorls (i.e. fused petals and stamens).
K(5) [ C 5 A 5 ] G(2)
= Actinomorphic
( ) united within organs
= Zygomorphic
[ ] united between organs
K = Calyx
C = Corolla
P = Tepals
A = Androecium
G = Gynoecium
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Flower Formula
Parentheses ( ) indicate if the organs within a whorl are united or fused
(i.e. united sepals) and brackets [ ] indicate if organs are united between
whorls (i.e. fused petals and stamens). The bridge symbol
is an
alternative to the brackets to indicate union between whorls.
K(5) [ C 5 A 5 ] G(2)
or
K(5) C 5 A 5 G(2)
= Actinomorphic
( ) united within organs
= Zygomorphic
[ ] united between organs
alternative to [ ]
K = Calyx
C = Corolla
P = Tepals
A = Androecium
G = Gynoecium
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Flower Formula
The letter “G” represents the gynoecium and if there is a line over the “G” it
indicates an inferior ovary, while a line below the “G” indicates a superior ovary.
K(5) [ C 5 A 5 ] G(2)
or
K(5) C 5 A 5 G(2)
= Actinomorphic
( ) united within organs
= Zygomorphic
[ ] united between organs
alternative to [ ]
K = Calyx
G inferior ovary
C = Corolla
G superior ovary
P = Tepals
A = Androecium
G = Gynoecium
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Flower Formula
There are two special symbols to indicate whether duplication has occurred
within a whorl. The infinity sign “ ∞ “ indicates that there are is a large
number of organs in a whorl (i.e. > 20 petals in a double flower). The plus sign
“+” is used to indicate that a whorl has duplicated (i.e. two sets of petals).
K(5) [ C 5 A 5 ] G(2)
or
K(5) C 5 A 5 G(2)
= Actinomorphic
( ) united within organs
= Zygomorphic
[ ] united between organs
alternative to [ ]
K = Calyx
G inferior ovary
C = Corolla
G superior ovary
P = Tepals
A = Androecium
G = Gynoecium
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Numbers indicate number
of organs in a whorl
∞ = large number
+ = more than one whorl
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Flower Formula
Therefore, this flower formula describes an actinomorphic flower with 5
sepals, 5 petals and 5 stamens. The 5 sepals are united. The petals and
stamens are united. The pistil has a superior ovary with two united carpels.
K(5) [ C 5 A 5 ] G(2)
or
K(5) C 5 A 5 G(2)
= Actinomorphic
( ) united within organs
= Zygomorphic
[ ] united between organs
alternative to [ ]
K = Calyx
G inferior ovary
C = Corolla
G superior ovary
P = Tepals
A = Androecium
G = Gynoecium
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Numbers indicate number
of organs in a whorl
∞ = large number
+ = more than one whorl
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Flower Formula
A more complicated flower formula is presented below. It describes an
actinomorphic flower with two whorls of 2 sepals, a single whorl of 4 petals, and
two whorls of 2 stamens. The pistil has an inferior ovary with 2 united carpels.
K2+2 C4 A2+2 G(2)
= Actinomorphic
( ) united within organs
= Zygomorphic
[ ] united between organs
alternative to [ ]
K = Calyx
G inferior ovary
C = Corolla
G superior ovary
P = Tepals
A = Androecium
G = Gynoecium
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Numbers indicate number
of organs in a whorl
∞ = large number
+ = more than one whorl
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Flower Formula
This flower formula describes a monocot flower. It is an actinomorphic
flower with two whorls of 3 tepals and two whorls of 3 stamens. The
pistil has a superior ovary with three united carpels.
P3+3 A3+3 G(3)
= Actinomorphic
( ) united within organs
= Zygomorphic
[ ] united between organs
alternative to [ ]
K = Calyx
G inferior ovary
C = Corolla
G superior ovary
P = Tepals
A = Androecium
G = Gynoecium
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Numbers indicate number
of organs in a whorl
∞ = large number
+ = more than one whorl
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