Gametophytes in angiosperms (flowering plants) have cells with half the number of chromosomes compared to the sporophyte generation. This is because they are produced through meiosis, a process that divides the chromosome number in half.

Here's a breakdown:

* Sporophyte: The diploid generation of a plant, which is the familiar plant you see with roots, stems, and leaves. These cells have the full set of chromosomes (2n).

* Gametophyte: The haploid generation of a plant, responsible for producing gametes (sex cells). These cells have half the number of chromosomes (n).

Therefore, the exact number of chromosomes in gametophyte cells depends on the specific species of angiosperm. For example, if a sporophyte has 24 chromosomes (2n = 24), the gametophyte will have 12 chromosomes (n = 12).

So, the answer is not a single number, but rather half the number of chromosomes found in the sporophyte generation of that specific angiosperm species.