Floral Formula and Floral Diagram

The below mentioned article provides a study note on the floral formula and the floral diagram.

Floral Formula:

It is sometimes found convenient to describe a flower by a simple and concise for­mula known as the floral formula. In this formula K represents calyx, C=corolla, P= perianth, A=androccium, G=Gynoecium.

The number of members of a whorl is written after the symbol for a whorl, ∞ signifies a large and indefinite number. If the members are present in different whorls, the different whorls are written separately with a + sign between them.

Thus, A₂₊₂ means androecium of four stamens in two whorls of two each. When members are united (cohesion), the number is placed within first brackets. Adhesion is expressed by a line joining the two whorls.

Superior or inferior position of gynoecium is denoted by a line below or above it. A male flower is signified by the

Floral Diagram:

It sometimes becomes very lucid if the ground plan of a flower be represented in the form of a floral diagram, in a floral diagram the position of the inflorescence axis or stem is shown by a dot or a small circle while the sepals, petals and stamens are put in concentric circles (or spirals when the floral phyllotaxy is spiral), the gynoecium being put at the centre.

It has become customary to represent petals by thick first brackets (representing t.s. of petals), sepals by the same symbol but showing the midrib, stamens by anthers and carpels by placentation.

The median (mm), lateral (ll) or diagonal planes  may be shown as straight lines. The bract may be shown by a second brac­ket. Thus, the orientation and symmetry of the flower and its different members may be shown very clearly. Adhesion and cohesion are shown by connecting lines.

The floral diagrams of some common flowers illustrating their constructions are shown .