From the evolutionary point of view, retention of the female gametophyte with developing young embryo on the parent sporophyte for some time, is first observed in _______________.

• In Pteridophytes, megaspore is retained for some times in female gametophyte. However, the permanent retention is required for seed formation and hence seed is not formed.
• That's why Pteridophytes are said to be precursors of seed habit.

So, the correct answer is 'Pteridophytes'