A cotyledon (/kɒtˈldən/; "seed leaf" frae Greek: κοτυληδών kotylēdōn, gen.: κοτυληδόνος kotylēdonos, frae κοτύλη kotýlē "cup, bowl") is a signeeficant pairt o the embryo athin the seed o a plant. On germination, the cotyledon mey become the embryonic first leafs o a settin. The nummer o cotyledons present is a characteristic uised bi botanists tae classify the flouerin plants (angiosperms). Species wi ane cotyledon are cried monocotyledonous ("monocots"). Plants wi twa embryonic leafs is termed dicotyledonous ("dicots") an placed in the class Magnoliopsida.

Cotyledon in formation afore the accumulation o the reserve seen at Judas-tree (Cercis siliquastrum)