Explanation:

(a) Phyllotaxy is the arrangement of leaves on a stem or axis. Phyllotaxy is usually of three types which are shown in the given figures A (alternate), B (opposite) and $\text{C}$ (whorled).
In alternate type, one leaf is borne at a node and leaves are arranged alternately giving a spiral form, e.g, mango, mustard and tobacco. In opposite arrangements, each node give rise to two leaves, arranged opposite to each other, e.g, Calotropis and guava plants. In whorled arrangement more than two leaves are formed from each node, e.g, Nerium.