In alternate phyllotaxy, how are leaves arranged?

• A. A single leaf arises at each node in an alternate manner
• B. A pair of leaves arise at each node and lie opposite to each other
• C. More than two leaves arise at a node and form a whorl
• D. Leaves arise only at the base

Answer: (A)

Alternate phyllotaxy means leaves are borne singly at each node, with the leaf position alternating to the opposite side of the stem as you move upward. This single-leaf-per-node pattern prevents pairs from lining up directly across from each other and creates a zigzag arrangement along the stem. This differs from opposite arrangement (two leaves at a node, directly opposite each other), whorled arrangement (three or more leaves at a node forming a circle), and basal or rosette patterns (leaves concentrated at the base rather than along the stem).