Poison oak typically has leaves composed of three leaflets, which is the most common form and the basis for the saying "leaves of three, let it be." However, it can sometimes have up to seven leaflets per leaf group, and in rare cases, even nine leaflets have been observed

. The leaflets resemble oak leaves, often with rounded teeth along the edges, and the plant can grow as a vine or shrub. The size of each leaflet ranges from about 1 to 4 inches long, and the leaves can vary in texture and color throughout the seasons

. In summary:

• Usually 3 leaflets per leaf
• Sometimes up to 7 leaflets, rarely more
• Leaflets look like oak leaves with rounded edges

This variability means that while the "three leaflets" rule is a good general guide, poison oak leaves can occasionally have more leaflets