Dicotyledon

A flowering plant whose embryo typically has two seed leaves, or cotyledons. The traditional group is not a natural evolutionary clade because monocots arose within it.

Cotyledon: A seed leaf in a plant embryo, which may store or absorb nutrients during germination. The two seed leaves give dicotyledons their name.
Seed: A mature plant ovule containing an embryo and stored resources, enclosed by a protective coat. Dicotyledon embryos develop within seeds alongside their cotyledons.
John Ray: An English naturalist whose seventeenth-century plant classification distinguished plants with one seed leaf from those with two. His classification helped establish the one-cotyledon and two-cotyledon distinction.
Monophyly: The condition in which a group contains a common ancestor and all of its descendants. Traditional dicotyledons fail this test because they exclude the nested monocots.
Angiosperm: A flowering plant that produces seeds enclosed within an ovary, which typically develops into a fruit. Dicotyledons are defined within this larger group of seed plants.
Plant embryo: The young plant formed within a seed after fertilization and before germination. Its body plan includes the cotyledons used to identify dicotyledons.
Antoine Laurent de Jussieu: A French botanist who organized plants into natural families in his 1789 work Genera Plantarum. His system formalized major flowering-plant groups that included dicotyledons.
Paraphyly: The condition in which a group includes a common ancestor but excludes some descendants. This describes the traditional dicotyledon grouping in modern evolutionary classifications.
Eudicot: A major clade of flowering plants characterized by pollen with three apertures or derived forms. Most plants traditionally called dicotyledons belong to this natural clade.
Seed germination: The resumption of growth by a seed embryo, leading to emergence of a seedling. Germination reveals whether cotyledons emerge or remain below ground.

Linked from 2 pages