A part of the embryo in a seed plant. The number of cotyledons is an important feature in classifying plants. Among the flowering plants, the monocots have a single cotyledon and the dicots have two. Conifers have either two cotyledons, as in Taxus (yews), or five to ten, as in Pinus (pines). In seeds without an endosperm, e.g. garden pea and broad bean, the cotyledons store food, which is used in germination. In seeds showing epigeal germination, e.g. runner bean, they emerge above the soil surface and become the first photosynthetic leaves.