Final answer:
Leaflets are characteristic of compound leaves, which can be palmately or pinnately structured, as seen in locust trees.
Step-by-step explanation:
Leaflets are a characteristic of compound leaves. In a compound leaf, the leaf blade is divided into separate segments known as leaflets. The two main types of compound leaves are palmately compound, where leaflets spread out from a single point like the palm of a hand, and pinnately compound, where leaflets are arrayed along a central midrib, resembling a feather's structure. An example of a plant with pinnately compound leaves is the locust tree, where each leaflet is attached to a rachis and may have its own stalk.