Solution-Class 9-Science-Chapter-6-Classification of Plants-Maharashtra Board

1. Thallophytaplants have soft and fibre-like body.

2. Bryophyteis called the ‘amphibian’ of the plant kingdom.

3. In pteridophytes, asexual reproduction occurs bysporeformation and sexual reproduction occurs by zygote formation.

4. Male and female flowers of gymnospermsare borne on different sporophylls of the same plant.

Plants that bear seeds are called Phanerogams. In these plants, seeds are formed after Reproduction.

They show characteristics like-

• Well-differentiated and visible reproductive tissues that ultimately make seeds.
• Seeds consists of the embryo along with stored food which helps in the initial growth of the embryo during germination

Phanerogams are further subdivided into gymnosperms and angiosperms on the basis of seeds which are enclosed in a fruit or not. Gymnosperms produce seeds which are not enclosed by fruit and hence are called naked seeds whereas angiosperms produce seeds which are enclosed in fruits.

Ferns are ornamental plants seen in gardens. They are called ornamentals as they beautify the place wherever they grow.

• Ferns belong to the division pteridophyta.
• The plant body of a pteridophyte is differentiated into root, stem and leaves.
• They are found in cool, damp and shady places and have specialized tissues for the conduction of water and food.
• Ferns are economically important plants as they are used for ornamental purposes.
• Since they are grown in gardens they do not bear flowers and fruits, but they bear different types of attractive leaves.
• They reproduce by spores which develop on the lower side of their leaflets in the form of sori.
• Some of the ornamental ferns are the Sword fern- Nephrolepis,  Holly fern - Cyrtomium, Leather leaf fern - Rumohra.

• Spirogyra is a type of green algae which belongs to the division Thallophyta.
• It does not have specific parts like leaves, stems etc.
• It grows in fresh water.
• It contains chlorophyll and is thus autotrophic in nature.
• It synthesises its food by the process of photosynthesis.
• It contains spiral chloroplasts and thin unbranched chains of cylindrical cells.
• In each chloroplast, there are a number of rounded bodies surrounded by starch. These rounded bodies are called pyrenoids.

The characteristics of bryophytes are-

• Plants belonging to the division Bryophyta are called amphibious plants as they grow in moist soil, but need water for reproduction, thus sharing two habitats.

• They are the first plants to live on land, but require moist conditions to survive. For this reason they are called ‘the amphibians of plant kingdom’.
• They are non-vascular, i.e., they do not have specialized vascular tissues (xylem and phloem) for the conduction of water and food.
• They lack true roots, stem and leaves. But, they show more body differentiation than thallophytes.
• The plant body of bryophytes is flat and ribbon like. They have rhizoids instead of true roots.
• They do not bear flowers and seeds.
• They reproduce both sexually as well as asexually.
• Bryophytes exhibits 'alternation of generations' in which gametophytic phase (haploid) alternates with sporophytic phase (diploid).
• Examples of bryophytes: Riccia, Marchantia, Anthoceros, unaria

• Marchantia is a bryophyte.
• Marchantia is called amphibious plant, as it shares two habitats, viz, soil for its growth and water for reproduction.
• It lacks conducting tissues which conduct food and water.
• It is flat ribbon-like long and without true roots, stem and leaves.
• Instead of roots, it bears rhizoids.

• Funaria is a bryophyte.
• Funaria is an amphibious plant.
• The plant body of Funaria is differentiated into stem-like parts, leaf-like parts and root-like rhizoids.
• It develops a capsule on a stalk during favorable conditions.
• Spores are formed inside the capsule. The spores give rise to new plants.

• Ferns belong to the division pteridophyta.
• The plant body of a pteridophyte is differentiated into root, stem and leaves.
• They are found in cool, damp and shady places and have specialized tissues for the conduction of water and food.
• They reproduce by spores which develop on the lower side of their leaflets in the form of sori.

• Spirogyra is a type of green algae which belongs to the division Thallophyta.
• It does not have specific parts like leaves, stems etc.
• It grows in fresh water.
• It contains chlorophyll and is thus autotrophic in nature.
• It synthesises its food by the process of photosynthesis.
• It contains spiral chloroplasts and thin unbranched chains of cylindrical cells.
• In each chloroplast, there are a number of rounded bodies surrounded by starch. These rounded bodies are called pyrenoids.

(1) Onion (Allium cepa) : An onion is monocotyledonous because the veins in the leaves are parallel, it has a fibrous root system and only one seed cotyledon . A small herb with tunicated bulb

Root : Fibrous

Stem : Underground stem (bulb)

Leaves : Hollow and tubular

Flower : Complete, bisexual

Perianth : Made up of 6 lobes, arranged in two whorls of 3 each

Androecium : Made up of 6 stamens, Epiphyllous

Gynoecium : Tricarpellary, syncarpous, ovary sperior.

(2) Hibiscus (A dicot plant) :

Root : Tap root

Stem : Erect and branched

Leaf : Simple, alternate, with reticulate, venation

Flower : Pedicillate, complete, bisexual

Calyx : Sepals-5, Gamosepalous

Corolla : Petals-5, Gamopetalous

Androecium : Stamen indefinite. Filaments are united to form a staminal tube. The staminal tube bears kidney shaped anthers.

Gynoecium ; Pentacarpellary, syncarpous.

Plants are divided on the basis of various characteristics like:

• There are two subkingdoms of flowering plants, viz., gymnosperms and angiosperms.
• Differentiation of plant body into roots, stem and leaves. Plants that are not differentiated into organs like roots, stem, leaves are called Thallophyta.
• Vascular tissues : Plants such as pteridophytes, gymnosperms and angiosperms which possess conducting tissues are included under vascular plants, while bryophytes and thallophytes which do not possess vascular tissues are included under non-vascular plants.

• Production of seeds : If plants do not bear flowers, fruits and seeds, they are non-seed-bearing plants. Contrary to this, if they bear flowers, fruits and seeds, they are seed-bearing plants.
• Covering of seeds : Depending upon whether the seeds are enclosed in fruits or not, plants have been classified as gymnosperms and angiosperms.

• Number of cotyledons in a seed : Depending upon the number of cotyledons in seeds, plants have been classified into diecotyledons and monocotyledons.