Floral Formula : Definitions, Components and Examples

SEMI-TECHNICAL DESCRIPTION OF A TYPICAL FLOWERING PLANT

Different characteristics of a family are the diagnostic features which enable us to differentiate them. These diagnostic features are mainly based on floral characters like sexuality of flowers, symmetry of flowers, position of ovary with respect to floral whorls, bracts, and conditions of calyx, corolla, androecium and gynoecium.

For a systematic study and quick comprehension of all the diagnostic features of a family, these characters are symbolised and put in the form of a floral formula. Floral diagrams are also drawn which give some extra informations like placentation, position of the mother axis, aestivation etc. Floral formulae and diagrams are given with the respective family descriptions later in the chapter.

Symbols used in Floral Formula

Symbol Description / Full form
Br Bracteate condition
Ebr Ebracteate condition
Brl Bracteolate
Epi Epicalyx (below sepals)
Ebrl Ebracteolate
0 (zero) Absence of a particular whorl
Indefinite number of floral parts in a whorl
Actinomorphic condition
% Zygomorphic condition
K
Kn
K(n)
Calyx (Sepals)
Polysepalous
Gamosepalous (where n : Number of sepals)
C
Cn
C(n)
Corolla (petals)
Polypetalous
Gamopetalous
P Perianth
A Androecium (stamens)
G Gynoecium (carpels)
Bisexual flower
Unisexual, staminate flower
♀️ Unisexual, pistillate flower
K5 Five sepals, aposepalous
K(5) Five sepals gamosepalous
C5 Five petals, apopetalous
C(5) Five petals, gamopetalous
Epiphyllous stamens Epiphyllous or Epitepalous stamens
Epipetalous stamens Epipetalous stamens
A3 Three stamens free
A2+2 Stamens 4, 2 whorls
A10+1 Stamens 10, diadelphous – 9 stamens unite to form one bundle and 1 other bundle
A0 Sterile stamen (staminode)
G0 Sterile carpel (pistillode)
G- Semi inferior ovary
Inferior ovary n Inferior ovary  (where n : Number of carpels)
Superior ovary n Superior ovary (where n : Number of carpels)

(14) In the floral diagram the dot (•) represents the position of mother axis. It denotes the posterior side of the flower.

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