cotyledon

views updated May 14 2018

cotyledon (seed leaf) 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 class known as Monocotyledoneae have a single cotyledon and Dicotyledoneae 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.

cotyledon

views updated Jun 08 2018

cot·y·le·don / ˌkätlˈēdn/ • n. Bot. an embryonic leaf in seed-bearing plants, one or more of which are the first leaves to appear from a germinating seed.DERIVATIVES: cot·y·le·don·ar·y / -ˈēdnˌerē/ adj.

cotyledon

views updated Jun 11 2018

cotyledon First leaf or pair of leaves produced by the embryo of a flowering plant. Its function is to store and digest food for the embryo plant, and, if it emerges above ground, to photosynthesize for seedling growth. See also dicotyledon; monocotyledon

cotyledon

views updated Jun 08 2018

cotyledon A seed leaf that is borne on a plant embryo. Characteristically there is 1 leaf in the monocotyledons, and 2 leaves in the dicotyledons, but there are exceptions, especially in the latter group.

cotyledon

views updated May 18 2018

cotyledon seed-leaf. XVIII. — L. cotylēdon navelwort, pennywort — Gr. kotúlēdṓn applied to various cup-shaped cavities, f. kotúlē hollow, cup.

cotyledon

views updated May 29 2018

cotyledon (kot-i-lee-dŏn) n. any of the major convex subdivisions of the mature placenta. Each cotyledon contains a major branch of the umbilical blood vessels.