Identify X
Pollen grain : Male gametophyte :: Stamen : X
Microsporophyll is the structure bearing the microsporangia which produce microspores. Stamen is considered as microsporophyll in angiosperms.
Megasporophyll is the structure bearing megasporangia. The carpel is considered as megasporophyll in angiosperms.
Thus pollen grain is also known as male gametophyte and stamen is also regarded as microsporophyll.