While the saying "leaves of three, let it be" is commonly associated with poison ivy, it's important to note that not all plants with three leaves are poison ivy. There are many other harmless plants that also have three leaves.

On the other hand, not all poison ivy plants have the typical three leaflets per leaf. Some poison ivy plants can have only one leaflet or five leaflets per leaf, making identification even more challenging.

To accurately identify poison ivy, it's essential to look for additional characteristics such as:

1. Leaf shape: Poison ivy leaves have smooth edges and a pointed tip.

2. Leaf color: The leaves can be green, reddish, or orange in color, depending on the season.

3. Leaf arrangement: Poison ivy leaves grow in an alternating pattern along the stem.

4. Stem color: The stems of poison ivy are often reddish or brown in color.

5. Presence of hairs: The stems and leaves of poison ivy may have small, fine hairs.

If you're unsure about whether a plant is poison ivy, it's best to avoid touching it and seek advice from an expert or a reliable plant identification guide.