Among the various groups of higher plants, bryophytes belong to a very special group. Its gametophyte is highly developed and assumes the functions of nutrition and reproduction. The sporophyte is parasitic on the gametophyte and cannot live independently. This structure, which is very different from other higher plants, has attracted the interest of many scientists, especially where bryophytes evolved. But so far, there is no reliable fossil evidence, and scientists can only speculate on the ancestors of bryophytes based on their body structure.
Many scientists believe that bryophytes evolved directly from algae, citing the existence of some intermediate types between modern bryophytes and algae. Among bryophytes, livers are a relatively primitive group. Among green algae, there are species with similar structures to liverheads. Similarly, among liverworts, the structure and shape of the genus Phyllodendron is similar to both liverworts and algae. Their gametophytes and archegonia structures are very simple and primitive. Therefore, it is generally believed that members of the genus Phyllodendron are the transition from algae to liverworts. An intermediate type.
However, some scientists believe that bryophytes evolved from the original fern, the naked fern, as a result of the gradual degradation of the sporophyte and the further complexity of the gametophyte. Some species of naked ferns have very simple morphological structures, much like bryophytes, and some species have sporangia structures similar to those of Shagnum and Black moss. Moreover, from a geological perspective, bryophytes appeared tens of millions of years later than naked ferns, which can also explain their evolutionary order.
All in all, bryophytes have become a blind branch in plant evolution. They are characterized by the independent life of gametophytes, while other higher plants tend to have more and more sporophytes, and the evolutionary directions of the two are opposite. The gametophyte is the product of asexual reproduction, while the sporophyte is the product of sexual reproduction. In comparison, the latter's vitality and development future are brighter. In fact, there are no higher groups in nature that have evolved from bryophytes.