Anatomy of Dicotyledonous and Monocotyledonous Plants

Tulips and daisies are both beautiful flowering plants. However, they do not fall into the same category of plants. Flowering plants are actually classified into two categories based on their embryo, called Monocotyledonous (monocot) plants and Dicotyledonous plants. Let us find out more about these plants.

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Dicotyledonous and Monocotyledonous Plants

Plants can be broadly classified into flowering and non-flowering plants. Flowering plants are called as angiosperms while non- flowering plants are known as gymnosperms. Angiosperms are further classified based on the nature of the embryo in the seed into Monocotyledonous and Dicotyledonous plants.

Dicots are plants that have seeds with two cotyledons and so are termed as dicotyledonous plants. Examples: Sunflower, Mango

Monocots are plants that have seeds with one cotyledon and so they are called as monocotyledonous (monocot) plants. Example: Sugarcane, Maize

Browse more Topics under Anatomy Of Flowering Plants

• Plant Tissues
• Tissue System
• Stem
• Leaf
• Inflorescence
• Secondary Growth
• Flower
• The Fruit
• The Seed
• Classification of Flowering Plants

Anatomy of Dicotyledonous and Monocotyledonous Plants

Both sets of plants differ structural features: Stems, leaves, flowers, and roots.

Dicotyledonous Plants

(Source: Plantlist)

Roots

• These plants have a tap root system
• They have two layers: the outermost epidermis which sometimes forms root hairs, the inner endodermis or the cortex.
• The epidermis consists of loosely packed cells whereas the endodermis has tightly packed cells.
• The central pith is inconspicuous.

Stems

• Stems are usually solid
• Cambium is present
• The number of xylem and phloem are two to four and they are distinguished by a layer of parenchymatous cells called conjunctive tissue.
• Vascular bundles in the stem are fewer and arranged in circles or rings
• Pith is evident as is made up of palisade cells
• Bundle sheath absent around vascular bundles
• Pericycle is present
• Phloem parenchyma and phloem fibres are present

Leaves

• They have reticulate or net venation
• Leaves have a stalk
• The mesophyll that contains chloroplasts is composed of spongy and parenchymatous cells

Flowers and seeds

• Flowers are usually pentamerous i.e the floral parts are present in numbers of five
• Seeds germination either hypogeal or epigeal.
• They have two cotyledons
• The pollen grains have three furrows or pores.

Examples of dicotyledonous plants: Tomatoes, Cauliflower, beans, apples, potatoes, etc

Monocotyledonous Plants

Roots

• They have an adventitious root system
• Pith is large and conspicuous
• The number of xylems is 6 or more
• Secondary growth is absent in monocots due to an absence of cambium

Stem

• No cambium and so no secondary growth in stem
• Stem usually hollow
• Vascular bundles in the stem are scattered and numerous
• Phloem parenchyma is absent
• Pith is absent
• Vascular bundles are surrounded by a sclerenchymatous bundle sheath
• Pericycle is absent

Leaves

• The leaves are sessile i.e it is directly attached to its base (without stalk)
• They have parallel venation
• Mesophyll is not differentiated into spongy and palisade cells

Flowers and seeds

• Seed germination is hypogeal
• They have a single cotyledon
• Flowers are incomplete and trimerous(floral parts are in the number of threes)
• The pollen grains have a single furrow or pore

Examples of monocotyledonous (monocot) plants: Maize, Corn, Grass, Wheat

Understanding the anatomy of these plants is useful from the horticultural and agricultural aspects. Choosing the right product for the right kind of plant is important. A herbicide or pesticide designed for a monocot might not help kill pests around a dicot. Due to the tap root system that is found in dicots, they can penetrate deeper into the soil compared to monocots who have a fibrous root system which cannot penetrate that deep.

Learn more about the concept of Tissue System here in detail.

Solved Example for You

Q: Which of the following are features of dicot plants

(a)    Taproot system         (b) Fibrous root system

(c)    Two cotyledons           (d) both a and c

Sol. (d) both a and c

Dicot plants have a taproot system, and seeds contain two cotyledons. The fibrous root system is found in monocots. So, the correct answer is (d) both a and c