Floral formulae

Floral Formulae

Representation of floral parts using numbers, letters and symbols. Provides information on symmetry, sexuality and interrelationship of calyx, corolla, androecium and gynoecium. Method used to record the structure of the flower.

Conveys information about the number and arrangement of different floral parts.

Flower symmetry

How flower can be divided into 2 or more identical images. Position and shape of perianth parts are important.

1. Actinomorphic (*): radial symmetry. Divide the flower in any plane from the centre to produce a mirror image. Primitive. Allows flower to attact pollinators from multiple directions.

2. Zygomorphic (%): Bilateral. Can cut the flower in only one plane from the center to get a mirror image or 2 similar halves.

3. Asymmetrical: cannot be divided into 2 identical halves. Don’t have any plane of symmetry.

Why?

Helps in identifying and naming flowers.

Provides basic information on floral morphology.

Important when classifying species or taxa.

Concise floral information for a species

How to write.

1. Symmetry

2. Sexuality

3. Sepals (P for tepals or Ca/K for calyx)

4. Petals (Co/C for corolla)

5. Stamen (A for androecium)

6. Carpels (G for gynoecium)

Note

If an organ type is arranged in more than one whorls or if the part differs in terms of arrangement/number the outermost is denoted 1st and the whorls are separated by +

If the organ number is large or fluctuating (use infinity sign)

If there is a variable number of a specific part (x)

The lack of a particular field (o)