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Learn about the Comparison of Ferns and Gymnosperms.
Ferns and Gymnosperms:
1. In both the groups there is alternation of generations but there is reduction in the gametophytic generation of the gymnosperms. In gymnosperms the gametophyte is reduced and is unlike that of ferns as it is completely dependent upon the sporophyte.
2. In gymnosperms there is gradual increase in the complexity of the sporophyte as it differentiates into root, stem and leaf. The tap root system becomes very well developed in gymnosperms and its continuous growth gives better anchorage and absorption of nutrients unlike the ferns in which the roots are always adventitious.
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3. The members of Cycadales resemble the ferns further in the compound nature of their leaves and in circinate vernation.
4. The companion cells remain absent from the phloem of both gymnosperms and ferns. The vessels are also not found in the xylem of all gymnosperms except the Gnetales where the vessels are present. Similarly phloem is composed of sieve cells and phloem parenchyma; companion cells are absent.
5. The gymnosperms resemble Selaginella, Isoetes, Marsilea and some fossil ferns in having heterospory. But in gymnosperms the spores germinate in situ the megaspore is retained within the mega-sporangium.
6. Multiflagellate and motile antherozoids are found in ferns as well as in Cycadales, but in other higher gymnosperms, such as the Coniferales and the Gnetales they are non-flagellate.
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7. There is excessive secondary growth in gymnosperms.
8. The seed-habit predominates in the gymnosperms and the angiosperms. However, the seeds were present in the fossil pteriodophytes but not in the living ones.
9. In gymnosperms the pollen grains are light, and develop partly before their release from the pollen sac.
10. In gymnosperms the fertilization is effected by pollen tube (i.e., siphonogamy) in contrast to zooidogamy in pteriodophytes where the motile sperms reach the eggs through neck canals or archegonia.
11. In gymnosperms the female gametophyte is permanently retained inside the megaspore. The archegonia of gymnosperms lack the neck canal cells and frequently the ventral canal cell is eliminated.
