Finally, these plants are gametophyte dominant, meaning that the recognizable stage of these plants is the haploid gametophyte generation. The seedless vascular plants, which include ferns and fern allies, possess several adaptations lacking in nonvascular plants.Xylem and phloem are present to efficiently transport water and sugars, respectively throughout the plant body.s photosynthetic autotrophs, plants use solar energy to produce organic compounds from carbon dioxide and water. The plant kingdom consists of four major groups: the nonvascular plants, the seedless vascular plants, the gymnosperms and the angiosperms.