The arrangement of flowers on the floral axis is termed inflorescence.
A kind of inflorescence in which the flowers are aligned in a seeming whorl, comprising a pair of opposite axillary, generally sessile cymes is verticillaster inflorescence.
A verticillaster refers to a fascicle with the composition of a dichasium, it is a common feature among the members of the Lamiaceae family.
Lamiaceae is a family of flowering plants generally known as the sage or mint family.
Some examples are basil, mint, rosemary, lavender, etc.
Tulsi or holy basil is a member of the family Lamiaceae, it exhibits verticillaster inflorescence.
In tulsi, two flower clusters each comprising three to nine flowers develop on a node on the axis of opposite leaves.