In this article we will discuss about the resemblances of gymnosperms with pteridophytes and angiosperms.
Resemblances of Gymnosperms with Pteridophytes:
1. Plant body is sporophytic, and the sporophyte is differentiated into roots, stem and leaves in both gymnosperms and pteridophytes.
2. Members of both the groups show a regular alternation of sporophytic and gametophytic generations.
3. Cercinate vernation of the young leaves is seen in both the groups.
4. Xylem consists of tracheids and xylem parenchyma. Vessels are absent in pteridophytes as well as gymnosperms (except Gnetales).
5. Phloem lacks companion cells in both the groups.
6. Heterospory is common in both gymnosperms and pteridophytes.
7. Gametophytic generation is dependent upon sporophytic generation.
8. Cycads resemble pteridophytes in possessing ciliated sperms.
9. Permanent retention of megaspores within the mega-sporangium is observed in both the groups.
10. “Ferns with seeds” (Pieridosperms) was the common name given to the primitive gymnosperms like Cycadofilicales due to their resemblances with the ferns.
Resemblances of Gymnosperms with Angiosperms:
Gymnosperms resemble angiosperms in the following features:
1. Presence of well-organized plant body, differentiated into roots, stem and leaves.
2. Presence of cambium in both gymnosperms and dicotyledons.
3. Presence of flowers in both the groups.
4. Presence of pollen tubes for carrying the male gametes to the female gamete.
5. Permanent retention of megaspore within the mega-sporangium in the members of both the groups.
6. Presence of integument around the ovule.
7. During the embryo development the suspensor formation is a constant feature.
8. Formation of seeds.
9. Close similarity in the general life history of members of both the groups.