In which group of plants do microspores and megaspores develop into separate male and female gametophytes?
Some pteridophytes (e.g., Selaginella, Salvinia) show heterospory, where microspores form male gametophytes and megaspores form female gametophytes. All gymnosperms are also heterosporous. Hence, the correct answer is "Pteridophytes and Gymnosperms".
Ref: NCERT Class 11 Biology Chapter 3: Plant Kingdom Pteridophytes - Structure and Life Cycle