Chapter 5

Morphology of Flowering Plants

The diversity of increasing plant structures will never fail to surprise us. Although angiosperms have a wide range of physical forms or morphology, they are always identified by their roots, stems, leaves, flowers, and fruits.

 

The term ‘morphology’ is derived from the ancient Greek words ‘morphe’, which means ‘shape’,  and ‘logos’, which means ‘study’. Morphology is thus the study of plants’ outward shape and internal structure and the ontogenic development of the plant body as a whole and its members. In Chapter 5 of Biology Class 11, we will focus on the morphology of flowering plants and related terms.

 

The form of vascular plants reflects their evolutionary history as terrestrial organisms that inhabit and draw nutrients from two different environments: underground and above-ground. They must take water and minerals from below the earth’s surface and carbon dioxide and light from above.

 

The potential to effectively gather these nutrients can be related to the development of roots, stems, and leaves as the three fundamental organs of plants. These combine to create a shoot system (developing from the plumule of the germinating seed) and a root system (growing from the germinating seed's radicle).

 

Topics covered in this chapter

 

1.

Introduction

2.

The root

3.

The stem

4.

The leaf

5.

The inflorescence

6.

The flower

7.

The fruit

8.

The seed

9.

Semi-technical description of a typical flowering plant

10.

Description of some important families

 

A flowering plant's morphology involves the stem, roots, leaves, flowers, and fruits, irrespective of the plant. Various morphological characteristics are required to classify a flowering plant. The plant is defined by its habit, vegetative characteristics, and floral characteristics like inflorescence and flower elements. After discussing different plant sections, a floral formula and a floral diagram are shown.


A typical flower includes four distinct whorls grouped sequentially on the inflated end of the stalk or pedicel, known as the thalamus or receptacle. These are the calyx, the androecium, the corolla, and the gynoecium. The calyx and corolla are considered the reproductive organs, whereas androecium and gynoecium are auxiliary organs. Chapter 5 Biology Class 11 NCERT Solutions covers all these aspects briefly.

A plant's root is a darkish, non-green, underground portion. A root system is a cluster of roots and their branches. The functions of roots are storage, absorption of water and minerals, and anchorage. The root system is classified into three types:

 

Tap root

Taproots are generally found in dicotyledonous plants. It grows from the germinating seed's radicle, together with its major roots and branches, giving birth to the taproot system. Examples: Mustard, mango, gram, banyan

 

Fibrous root

This system is found mainly in ferns and other monocotyledonous plants. This root grows from the stem and is formed of thin, modestly branched roots or main roots. Examples: Wheat, paddy, grass, carrots, onion, grass

Adventitious root 

The adventitious root system refers to roots that grow from any portion of the plant other than the radicle. This structure is found mainly in monocotyledonous plants.Examples: Maize, oak trees, banyan trees, horsetails

The stem is another essential component of the plant. It is the rising axis that bears branches, leaves, flowers, and fruits. It grows from the plumule of a developing seed embryo. Nodes and internodes are found on the stem. Nodes are the areas where leaves develop, while internodes are the areas between two nodes. The stem has buds that might be terminal or axillary. Primarily, the stem sends out branches to carry leaves, flowers, and fruits. It carries water, minerals, and photosynthates. Some stems store food or offer protection, support, and vegetative propagation.

The leaf is a flat, laterally borne structure. It is the primary photosynthetic component of plants. It absorbs light and aids gas exchange through the stomata.

 

The leaf base, petiole, and lamina are the leaf’s three primary sections. They develop at the node and produce a bud at the axil. Venation refers to the arrangement of veins and veinlets in a leaf. The presence of the photosynthetic pigment chlorophyll causes the leaves to appear green. Each leaf has a small hole or opening called stomata through which gaseous exchange occurs. The main functions of leaves are photosynthesis, storage, and transpiration.

A flower is a transformed shoot in which the shoot's apical meristem transforms into the floral meristem. The axis becomes condensed as the internodes do not expand. Instead of leaves, the apex develops different types of floral appendages laterally at consecutive nodes. 

The inflorescence is the arrangement of flowers along the floral axis. There are two sorts of inflorescences based on whether the apex turns into a flower or continues to develop – racemose and cymose. The primary axis of racemose inflorescences continues to develop, while the flowers are produced laterally in succession towards the apex.

Flowers are one of a plant’s main elements. Its purpose is to reproduce sexually. In angiosperms, the reproductive unit is the flower.

 

A typical flower comprises four distinct whorls positioned sequentially on the swelling end of the stalk or pedicel –  called the thalamus or receptacle. These are the calyx, the corolla, the androecium, and the gynoecium. Calyx and corolla are reproductive organs, whereas androecium and gynoecium are auxiliary organs.

Pollination is the process through which plants reproduce. It is the mechanism by which pollen is transferred from another flower to the stigma of the same or distinct plants.

 

A fruit is a mature or ripened ovary that has evolved after fertilization. A parthenocarpic fruit develops without the ovary being fertilized.

 

Generally, the fruit consists of a wall or pericarp and seeds. The pericarp might be meaty or dry. When the pericarp becomes thick and meaty, it is divided into the outside epicarp, the middle mesocarp, and the inside endocarp.

 

The fruit is called a drupe in mango and coconut. They have one seed and develop from monocarpellary superior ovaries.  The mesocarp of coconut is fibrous.

 

A seed is a fundamental component present inside the fruit. It consists of a seed coat and an embryo. The pericarp develops from the ovary wall during fruit formation.

Types of seeds

Seeds are categorized into two categories based on the number of cotyledons: 

         1.Monocotyledonous or monocot seeds: The embryo has just one cotyledon and is composed of an embryo axis. Monocot seeds include grains like rice, millet, and wheat and plants like onions, maize, ginger, banana, and palm.


2.Dicotyledonous or dicot seeds: The embryo has an embryo axis and two cotyledons. Dicot seeds include legumes like beans and lentils, peas, peanuts, and tomatoes.

A flowering plant is defined using various morphological features. The description must be concise, in basic scientific language, and in the correct order. The plant is described first with its habit, then with its vegetative characteristics – roots, stem, and leaves – and last with its floral characteristics – inflorescence and flower components.


Some symbols symbolize the flower formula. Br stands for bracteate in the flower formula. K stands for calyx, C for corolla, P for perianth, A for androecium and G for Gynoecium, G for superior ovary, and G for inferior ovary in male, female, or bisexual plants, ⊕ for actinomorphic and ·|· or ↑ for zygomorphic. Fusion is shown by enclosing the figure between brackets and attaching a line over the respective floral symbols.

Fabaceae (Fabaceae)

 

This family was previously known as Papilionoideae. It is a subfamily of the Leguminosae family. It is present globally.  

    • Trees, shrubs, and plants
    • Roots have nodules
    • The stem is erect or climber
    • Fruit is a legume with several non-endospermic seeds.
    • Alternate, pinnately complex, or simple leaves; pulvinate leaf base; stipulate; reticulate venation
    • Flower: Bisexual, zygomorphic
    • Inflorescence: Racemose
    • Calyx: Five gamosepalous petals, valvate/imbricate aestivation
    • Corolla: Five petals, polypetalous, papilionaceous, with a posterior standard, two lateral wings, and two anterior wings that form a keel (enclosing stamens and pistil), vexillary aestivation
    • Androecium: Ten, diadelphous, dithecous anther
    • Gynoecium: Superior ovary, monocarpellary, unilocular with numerous ovules, single style
    • Floral Formula: K(5) C1+2+(2) A(9)+1 G1 ·|·

1. Where can I find the NCERT Solutions for Class 11 Biology Chapter 5: Morphology of Flowering Plants?

Students can find NCERT Solutions for Class 11 Biology Chapter 5 on several educational platforms and the NCERT Solution Key. Subject matter experts specifically design the answers to help students easily master the topics. The answers are given in a PDF format, which students can download and use to solve their problems. They may depend on these answers confidently as they closely follow the most recent Term – I CBSE Syllabus for 2021–22 and its recommendations.

2. What are the subtopics of Class 11 Biology Chapter 5: Morphology of Flowering Plants? 

The sub-topics which are discussed in Chapter 5 of NCERT Solutions for Class 11 Biology are as follows:

    • The root 
    •  The stem 
    •  The leaf 
    •  The inflorescence 
    •  The flower 
    •  The fruit 
    •  The seed 
    •  Semi-technical description of a typical flowering plant 
    •  Description of some important families

3. What are the important questions of Class 11 Biology Chapter 5?

All the questions from this chapter, including examples and objectives, are important from the examination point of view. Therefore, it’s crucial to be through with Class 11th Biology Chapter 5 NCERT Solutions.

Other Courses

Related Chapters