Inflorescence, Flower and Floral Formula
Racemose and cymose patterns, floral parts, aestivation, placentation and symbolic floral notation. (Biology › Morphology of Flowering Plants, NEET UG syllabus.)
What is Inflorescence, Flower and Floral Formula?
The arrangement of flowers on the floral axis.
Key formula / rule: Floral Formula Notation
Key points
- To differentiate between racemose and cymose inflorescence with appropriate examples.
- To identify and describe the four whorls of a typical flower and their functions.
- To explain different types of aestivation and placentation with specific plant examples.
- To interpret and construct floral formulae for given flowers, understanding each symbol.
Common exam trap
Confusing acropetal (racemose) and basipetal (cymose) succession of flowers.
Definitions
- Term
Inflorescence
- Meaning
The arrangement of flowers on the floral axis.
- Term
Aestivation
- Meaning
The mode of arrangement of sepals or petals in a floral bud with respect to the other members of the same whorl.
- Term
Placentation
- Meaning
The arrangement of ovules within the ovary.
- Term
Floral Formula
- Meaning
A symbolic representation summarizing the floral characteristics of a plant, including symmetry, sex, and the number and arrangement of floral parts.
- Term
Actinomorphic
- Meaning
A flower that can be divided into two equal radial halves by any radial plane passing through the center (radially symmetrical).
- Term
Zygomorphic
- Meaning
A flower that can be divided into two similar halves only in one particular vertical plane (bilaterally symmetrical).
Learning objectives
To differentiate between racemose and cymose inflorescence with appropriate examples.
To identify and describe the four whorls of a typical flower and their functions.
To explain different types of aestivation and placentation with specific plant examples.
To interpret and construct floral formulae for given flowers, understanding each symbol.
To relate floral characteristics to the classification of flowering plants.
Formulae
- Name
Floral Formula Notation
- Note
Br: Bracteate, Ebr: Ebracteate; ⊕: Actinomorphic, %: Zygomorphic; ⚥: Bisexual, ♂: Male, ♀: Female; K: Calyx, C: Corolla, P: Perianth; A: Androecium, G: Gynoecium; (n): Fused parts, n: Free parts; _ (line below G): Superior ovary, _ (line above G): Inferior ovary; AC: Epipetalous, AP: Epiphyllous.
- Expression
Br/Ebr ⊕/% ⚥/♂/♀ K(n)/Kn C(n)/Cn P(n)/Pn A(n)/An G(n)/Gn
Prerequisites
Basic understanding of plant parts (root, stem, leaf).
Familiarity with fundamental biological terminology.
Common mistakes
Confusing acropetal (racemose) and basipetal (cymose) succession of flowers.
Mixing up examples for different types of aestivation or placentation.
Incorrectly interpreting or writing floral formulae, especially regarding fusion (brackets) and adhesion (line above symbols).
Misidentifying ovary position (superior, inferior, half-inferior) and their corresponding flower types (hypogynous, epigynous, perigynous).
Keywords
Inflorescence
Racemose
Cymose
Flower
Calyx
Corolla
Androecium
Gynoecium
Aestivation
Placentation
Floral Formula
Actinomorphic
Zygomorphic
Hypogynous
Epigynous
Ovary
Ovule
Thalamus
Practice preview
The outermost whorl of a flower, consisting of sepals, is known as the:…
easy
A flower with radial symmetry and a superior ovary is described as:…
medium
Which type of inflorescence exhibits continuous growth of the main axis and flowers arranged in an acropetal succession?…
easy