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Floral formula  [ Botany ]

Dictionary of botanic terminology - index of names

  A floral formula is a system of representing 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:

CaX = Calyx (sepal whorl) X = number of sepals (e.g. Ca5 = 5 sepals)
CoX = Corolla (petal whorl) X = number of petals (e.g., Co3(x) = petals some multiple of three )
Z = add if Zygomorphic (e.g., CoZ6 = zygomorphic with 6 petals)
AX = Androecium (whorl of stamens) X = number of stamens (e.g., A = many stamens)
GX = Gynoecium (ovary bearing carpels) X = number of carpels: if one, termed 'monocarpous', if two or more and free or distinct, termed 'apocarpous', if two or more and fused, termed 'syncarpous' or connate. (e.g., G1 = monocarpous)

A floral formula would appear something like this:


Other key used in Floral Formulas:

CaCo perianth; if sepals and petals are alike termed 'tepals'.

=  adnate; or fusion of two different floral whorls
= 'hypanthium' when all whorls are present. Especially frequent in the Rosidae. The floral whorls are perigynous to the gynoecium, which is still considered superior to them.

X   - to represent a "variable number"
- to represent "many"

X - X = variation in number in that family

X = X = Like floral parts in two whorls 

= fully fused or connate, especially in reference to the carpels of the gynoecium. If carpel # has no fusion symbol, carpels are free and distinct. 

= apically fused or connate

= basally fused or connate

= fully distinct or fused; variation within a family

= male unisexual flower

= female unisexual flower

= hermaphrodite bisexual flowers


* = staminode; a sterile stamen

= ovary inferior to insertion point of the other whorls. The floral whorls are epigynous to the gynoecium.

= ovary superior to insertion point of other floral whorls. The floral whorls are hypogenous to the gynoecium.

= ovary inferior to superior - variation exists

For example the floral formula of the Cactaceae Family is:








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