Which one of the following is heterosporous?
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Dryopteris
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Salvinia
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Adiantum
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Equisetum
B.
Salvinia
Heterospory is the production of spores of two different sizes and two different developmental patterns. Small spores are called microspores and larger as megaspore. Microspores germinate to produce the male gametophyte or microgametophyte that bear male sex organs while megaspores germinate to form female gametophyte or megagametophytes that bear archegonia or female sex organs. It is most important evolutionary development in the vascular plants because it has ultimately lead to seed development eg, Selaginella, Marselia Salvinia, Azolla, isoetes.
Dryopteris is homosporous a 32-64 haploid spores are produced in each sporangium.
Adiantum is also homosporous. The spores are the pioneer structures of the gametophytic generation.
