Angiosperms are further divided into monocots and dicots. They are distinguished by the characteristics of their cotyledons, leaf veins, roots, and stems.
Basic Knowledge
Dicotyledons (Dicotyledons): Rapeseed, dandelions, sunflowers, cherry trees, and others
・Cotyledons: 2
・Leaf veins: Netted venation (net-like)
・Roots: Taproot and lateral roots
・Vascular bundles in the stem: Arranged in a ring
Monocotyledons (Monocotyledons): Rice, corn, lilies, tulips, dayflowers, and others
・Cotyledons: 1
・Leaf veins: Parallel venation (parallel)
・Roots: Fibrous roots (many thin roots)
・Vascular bundles in the stem: Scattered (distributed separately)
Dicotyledons are further divided into sympetalous plants (petals joined together, such as morning glories and dandelions) and polypetalous plants (petals separate, such as rapeseed and cherry trees).
Cotyledon (cotyledon)（The first leaf to appear when a seed germinates）
Netted venation (netted venation)（Leaf veins form a net-like pattern. Dicotyledons）
Parallel venation (parallel venation)（Leaf veins run parallel. Monocotyledons）
Taproot and lateral roots（A thick central root and thin roots growing from it. Dicotyledons）
Fibrous roots（Many roots of similar thickness. Monocotyledons）
Vascular bundle (vascular bundle)（A bundle of tubes carrying water and nutrients. Xylem and phloem）
Further Study (Background and Significance)
The four characteristics (cotyledons, leaf veins, roots, and vascular bundles in stems) are interconnected. Dicotyledons consistently have two cotyledons → netted venation → taproots and lateral roots → vascular bundles arranged in a ring. These characteristics are evolutionarily related.
Dicotyledons account for about 75% of the world’s plants, and many vegetables we eat (tomatoes, eggplants, daikon radishes, carrots, and cabbages) are dicotyledons. Monocotyledons, on the other hand, include many grain crops used as staple foods (rice, wheat, and corn), supporting human food production.
Many monocots in the grass family are wind-pollinated flowers, characterized by reduced or inconspicuous petals. In contrast, dicots such as cherry trees and rapeseed are insect-pollinated flowers with colorful petals that attract insects.
Xylem (which carries water from roots to leaves) is on the inner side of a vascular bundle, while phloem (which carries nutrients from leaves to the rest of the plant) is on the outer side. This is also a structure shared by both dicots and monocots.
- Dicots: 2 cotyledons, netted venation, taproot and lateral roots, ring-shaped vascular bundles
- Monocots: 1 cotyledon, parallel venation, fibrous roots, scattered vascular bundles
- Dicots = cherry trees, rapeseed, dandelions
- Monocots = rice, corn, lilies, tulips
- Sympetalous plants (morning glories) and polypetalous plants (cherry trees)
- Xylem = pathway for water; phloem = pathway for nutrients
- The four characteristics are interconnected
Points to Note (Easily Confused)
① Two cotyledons = dicots, and one cotyledon = monocots. ② Netted venation = dicots, and parallel venation = monocots. ③ Do not reverse the correspondence between taproots + lateral roots (dicots) and fibrous roots (monocots). ④ Do not confuse the roles of xylem (water) and phloem (nutrients). Remember: “water = xylem.”
Practice
- Is rice a monocot or a dicot?
- What is the pattern of leaf veins in dicots called?
- What is the tube that carries water from roots to leaves called?