Pteridophyte Bryophyta Gymnosperm General Characteristics Examples

 PTERIDOPHYTE 

Definition: Seedless vascular cryptogams where the sporophytic plant body is differentiated into true root, stem and leaves are called pteridophytes.

General Characteristics :

1. Plant body is sporophyte which is differentiated into true stem, leaves and roots.

2 They occur in a variety of habitats. Mostly they are terrestrial plants and grow well in abundant moisture

and shaded localities. A few are aquatic, some others are epiphytic.

3. Primary roots are short-lived and are soon replaced by adventitious roots.

4. The stem is rhizomatous, branching is dichotomous or monopodial in some cases.

5. Leaves are of two types-microphyllous and megaphyllous. Microphyllous leaves are simple, small and have a single central vein not associated with leaf gap (e.g., Lycopodium, Selaginella). Megaphyllous leaves are compound, large-sized associated with leaf gap and are supplied with vascular bundles (e.g., Pteris).

A.Adiantum.  B. Dryopteris.    C.Sporophytic

Main Features of Pteridophytes :

1. These are non-flowering vascular plants.

2. Main plant body is a sporophyte.

3. Plant body has true root, stem and leaf.

4. Leaves are of two types-microphyllous and megaphyllous.

5. Young leaves show circinate vernation. [in few cases]

6. Xylem and phloem constitute the vascular system.

7. Embryo is formed and seeds are not formed.

Examples:

1. Dryopteris filix-mas 2. Lycopodium clavatum 3. Marsilea minuta

Economic Importances of Pteridophytes :

1. As Food: Young leaves of Marsilea, Dryopteris and Pteris are taken as food. The starchy paste of the sporocarps

of Marsilea sp. is prepared into cakes, commonly called nardoo by the natives of Australia.

2. As Medicine: Species of Lycopodium is widely used in homoeopathic system of medicine. Rhizomes and

petioles of Dryopteris yield an antihelminthic drug. Marsilin, an alkaloid, obtained from Marsilea is used in neurological problems.

Similarities between Bryophytes and Pteridophytes :

1. Both the groups show heteromorphic alternation of generations.

2. In both cases, gametophytes are parenchymatous and without any vascular tissues.

3. Terrestrial habitat.

4. Asexual reproduction by formation of spores.

5. Structures of male and female sex organs (antheridia and archegonia) are similar.

6. Male gametes are motile, female gametes are non-motile, sexual reproduction is oogamous type.

7. Fertilization occurs in presence of water.

8. Dependence of early embryo (sporophyte) upon the gametophyte.

Differences between Bryophyta and Pteridophyta:
Bryophyta

Bryophyta

1. The gametophyte (n) is the dominant phase.

2. Sporophyte is differentiated into foot, seta and capsule.

3. Absence of vascular tissues.

4. The sporophyte is dependent on the gametophyte.

5. Cone is not formed.

6. Bryophytes are homosporous.

7. Sporophyte bears no roots or rhizoids.

8. Sporophyll or sori are not formed.

9. Antherozoids are biflagellate.

10. Archegonia are long necked.

11. Archegonia secrete sugar before fertilization to attract

antherozoids.