dicotyledon, dicotyledonous, dicotyledonae, dicotyledoneae, dicotyledones

Pronunciation key

( dī′kot-ʼl-edʼn )
( dī-kot′ʼl-ē'dʼn )



A plant that produces two seed leaves (cotyledons). Any plant that is classed among one of the two subclasses of seed plants characteristically having two embryos with two cotyledons as most shrubs and deciduous trees.


Terms once used to classify species become outdated and are replaced as classification systems become more accurate. Currently, as it stands, the term Dicotyledoneae, (Taxonomic Serial No.: 206968) is invalid. The accepted name is Magnoliopsida.

Taxonomic Hierarchy
Kingdom Plantae – Vegetal, plants
Subkingdom Viridaeplantae – green plants
Infrakingdom Streptophyta – land plants
Division Tracheophyta – vascular plants, tracheophytes
Subdivision Spermatophytina – spermatophytes, seed plants
Infradivision Angiospermae – flowering plants, angiosperms
Class Magnoliopsida
Direct Children:
Superorder Amborellanae
Superorder Asteranae
Superorder Austrobaileyanae
Superorder Berberidopsidanae
Superorder Buxanae
Superorder Caryophyllanae
Superorder Ceratophyllanae
Superorder Dillenianae
Superorder Lilianae – monocots, monocotyledons
Superorder Magnolianae
Superorder Myrothamnanae
Superorder Nymphaeanae
Superorder Proteanae
Superorder Ranunculanae
Superorder Rosanae
Superorder Santalanae
Superorder Saxifraganae
Superorder Trochodendranae

Historically, dicotyledon were classed as such,

Subclass Dicotyledonae: the dicots. Flower parts are usually in fours or fives; leaf venation is usually netlike, pinnate, or palmate; there is true secondary growth with vascular cambium commonly present; there are two cotyledons; vascular bundles in the stem are in a ring; pollen is basically tricolpate. There are about 190,000 species.

Subclass Monocotyledonae: the monocots. Flower parts are usually in threes; leaf venation is usually parallel; true secondary growth is not present; there is one cotyledon; vascular bundles in the stem are scattered; the pollen is basically monocolpate. There are about 60,000 species.

Source: Biology of Plants, p. 660, Appendix C, ©1970, Worth Publishers, Inc., Peter H. Raven, Helena Curtis, Stanford University

di•cot•y•le•don•ous ( dī′kot-ʼl-edʼn-əs )
( dī-kot′ʼl-ed'n-əs )


Possessing two cotyledons and belonging to the subclass of dicotyledons.

References and Further Reading

  • Webster's New World Dictionary of the American Language (College Edition) ©1955
  • Biology of Plants, ©1970, Worth Publishers, Inc.
  • Magnoliopsida, Taxonomic Serial No.: 18063
  • The Monocot Class of Flowering Plants
  • Bean Seed Germination Photos
  • The Seed
  • Invalid subtaxa: Dicotyledonae [invalid subgroup], Dicotyledoneae [invalid subgroup], Dicotyledones [invalid subgroup]
  • Traditional Classification of Plant Families Table gives the traditional classification of Plant Families into their Orders and Superorders, in the Subclasses Dicotyledonae and Monocotyledonae, in the Class Gymnospermae.
  • Magnoliopsida (Synonyms Dicotyledons)
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