Meiosis is best observed in dividing

Meiosis is best observed in dividing microsporocytes.
The male gametophyte is initiated in the flower within anther sacs. Their precursors consist of large cells found in a stacked column near the center of the anther sacs; these cells are known as microsporocytes.
A diploid cell undergoes meiosis to produce microspores as part of microsporogenesis. Also called microspore mother cell pollen mother cell.