Question

Answer the following questions in your own words.

a. Write the charateristics of subkingdom Phanerogams.

b. Distinguish between monocots and dicots.

c. Write a paragraph in your own words about the ornamental plants called ferns.

d. Sketch, label and describe the Spirogyra.

e. Write the characteristics of the plants belonging to division Bryophyta.

Answer 1

a. The word ‘Phanerogamae’ comprises the words ‘phaneros’ meaning ‘visible’ and ‘gamos’ implying ‘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.


b.

Monocots	Dicots
The embryo in a monocot seed has one cotyledon.	The embryo in a dicot seed has two cotyledons.
The sepals or petals are in multiples of three.	The sepals or petals are in multiples of four or five.
The stem vascular bundles are scattered.	The stem vascular bundles are arranged in a ring.
The leaves have parallel venation.	The leaves have reticulate venation.
They have fibrous or adventitious roots.	They have a tap-root system.

c. 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. Some of the ornamental ferns are the sword fern- Nephrolepis, the holly fern - Cyrtomium, the leatherleaf fern - Rumohra.

d. Spirogyra is a type of green algae which belongs to the division Thallophyta. It does not have specific parts like leaves, stems etc. It contains chlorophyll and is thus autotrophic in nature. It contains spiral chloroplasts and thin unbranched chains of cylindrical cells.



e. The characteristics of bryophytes are-

• 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.
• 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, Funaria