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- https://bio.libretexts.org/Courses/University_of_California_Davis/PLS_002%3A_Botany_and_physiology_of_cultivated_plants/03%3A_Origin_and_evolution_of_land_plants/3.02%3A_Biodiversity_(Organismal_Groups)/3.2.03%3A_Seed_Plants/3.2.3.02%3A_GymnospermsIn gymnosperms, protective seeds filled with nutritive tissue (including the megagametophtye) replace spores as the dispersal mechanism. Antheridia are lost in the microgametophyte, which is reduced t...In gymnosperms, protective seeds filled with nutritive tissue (including the megagametophtye) replace spores as the dispersal mechanism. Antheridia are lost in the microgametophyte, which is reduced to four cells and is dispersed as a whole (pollen). The evolution of secondary growth allows for the lateral deposition of woody tissues. This latter development, along with xerophytic leaves, allows gymnosperms to tolerate a wide variety of new environmental stressors.
- https://bio.libretexts.org/Bookshelves/Botany/Botany_(Ha_Morrow_and_Algiers)/02%3A_Biodiversity_(Organismal_Groups)/2.06%3A_Seed_Plants/2.6.02%3A_GymnospermsIn gymnosperms, protective seeds filled with nutritive tissue (including the megagametophtye) replace spores as the dispersal mechanism. Antheridia are lost in the microgametophyte, which is reduced t...In gymnosperms, protective seeds filled with nutritive tissue (including the megagametophtye) replace spores as the dispersal mechanism. Antheridia are lost in the microgametophyte, which is reduced to four cells and is dispersed as a whole (pollen). The evolution of secondary growth allows for the lateral deposition of woody tissues. This latter development, along with xerophytic leaves, allows gymnosperms to tolerate a wide variety of new environmental stressors.
- https://bio.libretexts.org/Courses/Coalinga_College/Introduction_to_Plant_Science_(Hochman_Adler)/14%3A_The_Origin_of_Trees_and_Seeds/14.06%3A_Spermatophyta_-_Seed_PlantsOn the other hand, Ephedra and Gnetum have double fertilizationthe process when two brother male gametes fertilize two sister female cells: both male nuclei fuse with cells of the one female gametophy...On the other hand, Ephedra and Gnetum have double fertilizationthe process when two brother male gametes fertilize two sister female cells: both male nuclei fuse with cells of the one female gametophyte (endosperm1): with egg cell and another haploid cell, sister to the egg.
- https://bio.libretexts.org/Bookshelves/Botany/Introduction_to_Botany_(Shipunov)/07%3A_The_Origin_of_Trees_and_Seeds/7.06%3A_Spermatophyta_-_Seed_PlantsSeed plants consist of approximately 1,000 species of non-angiosperms (gymnosperms) and about 250,000 species of angiosperms. They have a sporic life-cycle with sporophyte predominance, and seeds. The...Seed plants consist of approximately 1,000 species of non-angiosperms (gymnosperms) and about 250,000 species of angiosperms. They have a sporic life-cycle with sporophyte predominance, and seeds. The gametophyte is reduced to cells inside the ovule or pollen grain. Males have a minimum number of cells being three and females being four. The antheridia are absent and in flowering plants (Angiospermae) and Gnetopsida the archegonia are also reduced.
- https://bio.libretexts.org/Courses/Norco_College/BIO_5%3A_General_Botany_(Friedrich_Finnern)/21%3A_Seed_Plants/21.02%3A_GymnospermsIn gymnosperms, protective seeds filled with nutritive tissue (including the megagametophtye) replace spores as the dispersal mechanism. Antheridia are lost in the microgametophyte, which is reduced t...In gymnosperms, protective seeds filled with nutritive tissue (including the megagametophtye) replace spores as the dispersal mechanism. Antheridia are lost in the microgametophyte, which is reduced to four cells and is dispersed as a whole (pollen). The evolution of secondary growth allows for the lateral deposition of woody tissues. This latter development, along with xerophytic leaves, allows gymnosperms to tolerate a wide variety of new environmental stressors.
