What Is a Dicotyledonous Plant?

What Is a Dicotyledonous Plant? image by Photo by Tico Bassie (http://www.flickr.com/photos/tico_bassie/120810354/)
What Is a Dicotyledonous Plant? image by Photo by Tico Bassie (http://www.flickr.com/photos/tico_bassie/120810354/)


Several criteria are used to classify plants. Historically, flower morphology has been the primary determinant of classification, but biochemical and genetic data are increasingly important. The two major plant phyla are the gymnosperms (conifers, cycads, Ginkgo) and angiosperms (flowering plants). The Angiosperms are further divided into two major classes---the Monocotyledonae (monocots) and the Dicotyledonae (dicots).


The division of flowering plants into monocots and dicots was first proposed by John Ray in 1682. In modern taxonomy, the classes Magnoliopsida (dicots) and the Liliopsida (monocots) are often used.

Definition of a Dicot

A dicot is so named, because it produces two special leaves---the cotyledons---upon germination. These embryonic leaves are "seed leaves" that quickly fall off or shrivel up, and they do not look like the later leaves that are typical of the plant.

Dicot Roots

Dicots generally have a distinct taproot with a few major lateral branches. The roots are seldom fibrous as they are in monocots.

Dicot Shoots

In dicots, the vascular bundles (xylem and phloem) are arranged in a ring close to the outside the stems. In monocot stems, the vascular bundles are arranged more randomly.

Dicot Leaves

Dicot leaf veins form branched networks, often described as net-like. Monocots have veins running parallel to the length of the leaves.

Dicot Flowers

Dicot flower petals are usually found in multiples of four or five. Monocot petals occur in multiples of three and are limited to a maximum of six.


  • Vascular Plant Families; James P. Smith; Madd River Press, Eureka, CA; 1977
  • Class Magoliopsida (Dicots)

Who Can Help

  • Monocots vs. Dicots: The Two Classes of Flowering Plants

About this Author

Philip McIntosh has more than 30 years of experience as an equipment engineer, scientific investigator and educator. He has been writing for 16 years, and his work has appeared in scientific journals, popular science magazines, trade journals and on science and technology websites. McIntosh holds a B.S. in botany and chemistry, and an M.A. in biological science.

Photo by: Photo by Tico Bassie (http://www.flickr.com/photos/tico_bassie/120810354/)