Pteridophytes are a group of plants that belong to the division Pteridophyta. They are commonly referred to as ferns and their distinguishing feature is that they do not produce seeds. This sets them apart from the rest of the tracheophytes, which include gymnosperms and angiosperms.

Pteridophytes have a unique life cycle that involves the alternation of generations between a sporophyte and a gametophyte. The sporophyte is the dominant phase and is the plant that we commonly recognize as a fern. It produces spores through meiosis, which are dispersed into the environment. These spores eventually germinate and give rise to the gametophyte phase.

The gametophyte is a small, independent plant that produces the gametes (sperm and eggs). Fertilization occurs when the sperm swim through a film of water to reach the eggs on the gametophyte. This dependence on water for fertilization is another characteristic that distinguishes pteridophytes from gymnosperms and angiosperms, which have evolved various mechanisms for seed dispersal and fertilization without the need for water.

Once fertilization occurs, the zygote develops into a new sporophyte, completing the life cycle of the pteridophyte. The sporophyte grows from the gametophyte and eventually becomes independent. It produces leaves, stems, and roots, and continues to produce spores through meiosis.

In contrast, gymnosperms and angiosperms have evolved to produce seeds, which protect and nourish the developing embryo. Seeds are dispersed by various means such as wind, water, or animals, allowing for greater colonization and survival. This adaptation has allowed gymnosperms and angiosperms to dominate the plant kingdom and occupy a wide range of habitats.

In summary, pteridophytes differ from the rest of the tracheophytes in that they do not produce seeds. Instead, they have a unique life cycle that involves the alternation of generations between a sporophyte and a gametophyte. This dependence on water for fertilization and the absence of seeds are key characteristics that set pteridophytes apart from other tracheophytes.