Here's why:

* Gametophyte: This is the haploid phase of the plant life cycle where the plant produces gametes (sex cells). In Bryophytes, the gametophyte is the larger, more conspicuous, and longer-lived phase.

* Sporophyte: This is the diploid phase of the plant life cycle where the plant produces spores. In Bryophytes, the sporophyte is smaller, dependent on the gametophyte for nutrition, and relatively short-lived.

Therefore, the gametophyte generation is the dominant phase in the Bryophyte life cycle.