Question
Question: Thallophyte, Bryophyte and Pteridophyte are called Cryptogams. Gymnosperms and Angiosperms are calle...
Thallophyte, Bryophyte and Pteridophyte are called Cryptogams. Gymnosperms and Angiosperms are called Phanerogams. Why?
Solution
The plant kingdom includes primitive plants as well as advanced plants. Primitive plants have less advanced features while advanced ones are developed plants. The plant kingdom can broadly be divided into Cryptogams and Phanerogams.
Complete answer:
Cryptogams are spore bearing plants. They reproduce by means of spore production. The word Cryptogam comes from the word ‘crypto’ which means concealed or hidden. The plants that belong to this group do not bear seeds and are said to have concealed reproductive organs, hence the name. The typical characteristics of this group of plants are mentioned below:
-Cryptogams are lower plants that do not bear seeds or flowers.
-The body of these plants are not differentiated into root, stem or leaves.
-The mode of reproduction can be vegetative, sexual and asexual.
-In advanced cryptogams, alternation of generation is generally seen. The life cycle is completed in alternating sporophytic and gametophytic stages. The gametophyte stage is the haploid stage while the sporophyte stage is the diploid stage.
Cryptogams comprise the Thallophyte, Pteridophyte and Bryophyte. Thallophytes are lower plants. Their body is not differentiated into root, leaves and stem. Bacteria, fungi, lichens belong to this group. Bryophytes can be found both on land and in water. They have roots like rhizoids in their body that help the plants to anchor themselves. Liverworts and mosses are typical Bryophytes. Pteridophytes are the advanced cryptogams. Their body is differentiated into roots, stem and leaves. This group includes ferns of all kinds.
Phanerogams are seed bearing plants. The word Phanerogams is derived from ‘phaneros’ meaning visible. Phanerogams reproduce by means of seeds and are also known as seed plants. The typical characteristics of Phanerogams are listed below:
-The phanerogams’ body is divided into root, stem and leaves.
-They contain chlorophyll and are capable of producing their own food.
-Phanerogams have well-developed vascular tissues.
-The reproductive parts of the plants are present in flowers and hence, visible.
-The life cycle is completed in two phases – sporophytic and gametophytic phases. However, the gametophytic phase is reduced as compared to that of the Cryptogams.
Phanerogams include Gymnosperms and Angiosperms. Gymnosperms are plants that produce naked seeds, that is, the seeds are not enclosed in fruits. These plants are generally woody plants that do not produce flowers. Cycas, Ginkgo and Pine are examples of Gymnosperms. Angiosperms are flowering plants that bear seeds in fruits. Typical Angiosperms are maize, pea, sunflower, mustard etc.
Note: Cryptogams and Phanerogams are two broad divisions of the plant kingdom. Cryptogams are primitive type plants with less developed body structure as compared to the Phanerogams, which have well differentiated and well-developed body parts. The cryptogams have concealed reproductive parts as opposed to visible ones of the Phanerogams.