What defines a monocotyledon?

A monocotyledon, commonly referred to as a monocot, is characterized by having an embryo with a single seed leaf, or cotyledon. This defining feature sets monocots apart from dicotyledons (dicots), which have two seed leaves. The single cotyledon in monocots is crucial as it plays a significant role in the initial stages of seedling development, providing nutrients to the emerging plant until it can photosynthesize on its own.

Monocots also typically exhibit other characteristics, such as parallel leaf venation, flower parts in multiples of three, and fibrous root systems, but the key defining aspect is indeed the single seed leaf. Recognizing this trait is essential for understanding plant classification and biology.