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Learn about the comparison among bryophytes, pteridophytes and gymnosperms.
Comparison # Bryophytes:
1. Sporophytic Plant Body:
In bryophytes, monosporangiate thalloid or foliose; roots are absent.
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2. Vascular System:
No Vascular System is present is bryophytes.
3. Leaf:
No circinate vernation in young leaf
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4. Sporangium:
Sporangium is dehiscent in bryophytes.
5. Spore:
Homosporous
6. Sex Organs:
Antheridium and archegonium
7. Male Gamate:
Flagellated and Motile
8. Fertilization:
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In bryophytes, fertilisation is not siphonogamous; water is essential
9. Seed:
No seed is present in bryophytes.
10. Alteration of Generation:
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Heteromorphic alteration of generations. Gametophyte is predominant; sporophyte is completely dependent on gametophyte.
Comparison # Pteridophytes:
1. Sporophytic Plant Body:
Polysporangiate, differentiated into root, stem and leaves; true roots are absent in some species (e.g., Psilotum)
2. Vascular System:
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In pteridophytes, vascular system is present; however, the xylem is without vessels (except,. Selaginella, Marsilea) and phloem is without companian cells
3. Leaf:
Circinate vernation in young leaf
4. Sporangium:
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Sporangium is dehiscent in Pteridophytes.
5. Spore:
Both homosporous (Psilotum, Lycopodium) and heterosporous (e.g., Selaginella)
6. Sex Organs:
Antheridium and archegonium
7. Male Gamate:
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Flagellated and Motile
8. Fertilization:
Not siphonogamous; water is essential
9. Seed:
No seed is present in pteridophytes.
10. Alteration of Generation:
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Heteromorphic alteration of generations. Sporophyte is dominant. Gametophyte is small inconspicuous but independent of sporophyte.
Comparison # Gymnosperms:
1. Gymnosperms:
Polysporangiate, differentiated into roots, stem and leaves.
2. Vascular System:
In gymnosperms, vascular system present like Pteridophytes; However, the members of Gnetales (e.g., Gnetum) possess vessels and companion cells in xylem and phloem, respectively.
3. Leaf:
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No circinate vernation except Cycas.
4. Sporangium:
Microsporangium is dehiscent, but megasporangium is indehiscent in gymnosperms.
5. Spore:
Heterosporous.
6. Sex Organs:
Antheridium and archegonium; however, neck canal cells are absent in the archegonium of Gymnosperm. Moreover, archegonium is absent in Gnetum.
7. Male Gamate:
Mostly non-motile except in Cycas and Ginkgo, where they are ciliated.
8. Fertilisation:
Siphonogamous; water is generally not required.
9. Seed:
Formation of seeds occur in gymnosperms.
10. Alternation of Generation:
Heteromorphic alternation of generations, sporophyte dominant; gametophyte is reduced.
