Pinnately compound leaves

Definition

Pinnately compound leaves have a central rachis with multiple leaflets arranged along each side, resembling a feather's structure. Each leaflet is attached to the rachis by its own stalk called a petiolule.

5 Must Know Facts For Your Next Test

1. Pinnately compound leaves can be either once-pinnate or twice-pinnate (bipinnate), depending on the level of leaflet division.
2. The central axis in pinnately compound leaves is known as the rachis.
3. Examples of plants with pinnately compound leaves include rose, ash, and pecan trees.
4. Each leaflet in a pinnately compound leaf has its own small stalk called a petiolule.
5. Pinnately compound leaves differ from palmately compound leaves where all leaflets arise from a single point.

Review Questions

• What distinguishes pinnately compound leaves from palmately compound leaves?
• Name two plant species that exhibit pinnately compound leaves.
• What is the term for the central axis in pinnately compound leaves?

Related terms

Rachis: The main axis or stem in a pinnately compound leaf that holds the leaflets.

Petiole: The stalk that attaches a single leaf to the stem or branch of a plant.

Palmately Compound Leaves: Leaves where all the leaflets originate from a single point at the end of the petiole, resembling an open hand.