In which group of plants do male and female gametophytes not have an independent existence?

In angiosperms, male and female gametophytes do not exist independently; instead, they are developed within the structures of the parent plant. In angiosperms, the male gametophyte is represented by pollen grains, which develop from microspores within the anthers of flowers. The female gametophyte, known as the embryo sac, develops from megaspores within the ovules located in the ovary of the flower.

This encapsulated development of gametophytes is significant because it provides them with protection and nourishment from the sporophyte, which enhances their chances of successful fertilization and subsequent seed development. This contrasts with other plant groups where gametophytes can be free-living and independent, such as in pteridophytes, where the gametophyte is a separate and photosynthetic entity, or in algae, where both gametophytes and sporophytes may exist independently in many species.

In summary, in angiosperms, male and female gametophytes rely entirely on the parent sporophyte for their existence, indicating a further advancement in plant evolution.