$(i)$ A typical angiospermic anther is a bilobed structure having two theca at each lobe

$(ii)$ It is tetragonal in shape with 4 microsporangia located at each lobe in its corners

$(iii)$ Microsporangia develop into pollen sac, which produces pollen

$(a)$ A typical stamen

$(b)$ Three-dimensional cut section of an anther