During division the generative cell is located in the centre of the pollen grain, near to the nucleus of a surrounding vegetative cell.

What is the generative nucleus?

: the one of the two nuclei resulting from the first division in the pollen grain of a seed plant that gives rise to sperm nuclei — compare tube nucleus.

What is generative cell?

[ jĕn′ər-ə-tĭv ] A cell of the male gametophyte (pollen grain) of seed plants that divides to give rise directly or indirectly to sperm.