Bryophytes are nonvascular; all other plants have vascular tissue sometime in life cycle. Three separate divisions include: hornworts, liverworts, and mosses. Lack true roots, stems, or leaves with vascular tissues; structures are only rootlike, stemlike, or leaflike. Gametophyte is dominant generation. a. Flagellated sperm swim in water in vicinity of egg. b. Sporophyte develops from zygote and is attached to and derives nourishment from gametophyte.