90 SOUTH AFRICAN BOTANY 
or ASYMMETRICAL, having no plane of symmetry, e.g. 
Cactus. 
57. Cohesion and Adhesion.— When similar parts of a 
plant are united we use the term Couxsion. Thus we 
speak of the cohesion of sepals in a gamosepalous calyx. 
But when dissimilar parts are united we use the term 
ADHESION. Thus we speak of the adhesion of the 
stamens to the petals, of the calyx to the ovary, etc. 
58. Floral Diagrams and Formulae.—It is very useful 
in describing a flower to draw a diagram of the arrange- 
ment of its members as they are seen in a cross-section 
of the opened bud, so arranged that the transverse sec- 
tion of the axis of the inflorescence stands above and 
that of the bract below. Such a diagram is called a 
Frorat DiacrAm. Cohesion of parts may be indicated 
by connecting lines, and aestivation of the perianth 
may be shown on it as well. A diagram representing 
the vertical section of the flower should also accompany 
the floral diagram as this gives further information 
which it is impossible to insert in the floral diagram, 
e.g. whether flower 1s hypogynous, epigynous, or peri- 
gynous. 
Similarly FLoRAL FormMuLAE enable us to describe 
very shortly the number of members in each whorl of a 
flower, and certain facts about their arrangement. In 
these formulae, the letters K, C, A,and G, stand for 
calyx, corolla, androecium and gynoecium respectively. 
The number which follows these letters gives the number 
of sepals, petals, stamens or carpels. Cohesion is indi- 
cated by brackets enclosing the number of parts. A 
horizontal bracket indicates adhesion between the parts 
