A and B are twigs with with 20 leaves each. A belongs China-rose and B to Calotropis. Then how many nodes are present in twig A and twig B respectively.

China-rose has alternate phyllotaxy i.e. every node has only one leaf. Hence twig A has 20 nodes. Twig B of Calotropis has opposite phyllotaxy with two leaves at each node. 20 leaves are present at 10 nodes.