Semi-Technical Description of a Typical Flowering Plant

SEMI-TECHNICAL DESCRIPTION OF A TYPICAL ANGIOSPERMIC PLANT

Different characteristics of a family are the diagnotistic 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

(1) Br : Bracteate flower

(2) Ebr : Ebracteate flower (bract absent)

(3)  : Actinomorphic flower

(4) % or + : Zygomorphic flower

(5)   : Bisexual flower

(6) : Unisexual, male flower

(7) : Unisexual; female flower

(8) K : Calyx

K_n : Polysepalous

K_(n) : Gamosepalous
where n = Number of sepals

(9) Epi : Epicalyx (below sepals)

(10) C : Corolla

C_n : Polypetalous
C_(n) : Gamopetalous
where n = Number of petals

(11) P : Perianth

(12) A : Androecium

: Infinite stamens

: Epipetalous stamens

: Epitepalous or epiphyllous stamens

(13) G : Gynoecium

G_(n) : Syncarpous ovary

G_n : Apocarpous ovary

G_n : Superior ovary

: Inferior 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.