What leaf characteristic is often used to help identify plants?

Leaf arrangement is a crucial characteristic used in plant identification because it describes how leaves are positioned on the stem. This can vary significantly among different plant species and can provide key insights into a plant's identity. For example, leaves may be arranged in a whorled pattern, alternate positions, or opposite each other on the stem. These patterns can help distinguish between species that may otherwise appear similar.

In contrast, while leaf thickness, color, and size can also play a role in identification, they can be much more variable within a species or influenced by environmental factors, making them less reliable as distinguishing features. Leaf arrangement, being a more consistent trait across different species, is often emphasized in botany and horticulture for effective plant identification.