An embryonic leaf in seed-bearing plants, one or more of which are the first leaves to appear from a germinating seed.‘The cotyledons are the ‘seed leaves’ produced by the embryo.’
- ‘However, protein biosynthesis in the axis organs and cotyledons of dicotyledonous seeds commences much earlier.’
- ‘Mutants of this class display shortened hypocotyls and small cotyledons after irradiation of seed.’
- ‘They are present on the stems, leaves, cotyledons, rachises, pedicles, bracts and calyces.’
- ‘The layer between seed coat and cotyledon probably includes the wall of the embryo sac.’
2A succulent plant of the stonecrop family, some kinds of which are grown as ornamentals.
Genus Cotyledon and related genera, family Crassulaceae: several species
Mid 16th century (denoting a patch of villi on the placenta of mammals): from Latin, ‘navelwort’ (which has cup-shaped leaves), from Greek kotulēdōn ‘cup-shaped cavity’, from kotulē ‘cup’.