Bryophytes are characteristically limited in size and prefer moist habitats although some species can survive in drier environments.

Gametophytes produce haploid sperm and eggs which fuse to form diploid zygotes that grow into sporophytes.

Gametangia (gamete-producing organs), archegonia and antheridia, are produced on the gametophytes, sometimes at the tips of shoots, in the axils of leaves or hidden under thalli.

Thus bryophytes disperse by a combination of swimming sperm and spores, in a manner similar to lycophytes, ferns and other cryptogams.

In hornworts, the meristem starts at the base where the foot ends, and the division of cells pushes the sporophyte body upwards.

[17] Traditionally, all living land plants without vascular tissues were classified in a single taxonomic group, often a division (or phylum).

[18] As early as 1879, the term Bryophyta was used by German bryologist Wilhelm Schimper to describe a group containing all three bryophyte clades (though at the time, hornworts were considered part of the liverworts).

[20] Although a 2005 study supported this traditional monophyletic view,[21] by 2010 a broad consensus had emerged among systematists that bryophytes as a whole are not a natural group (i.e., are paraphyletic).

[25] Since then, partially thanks to a proliferation of genomic and transcriptomic datasets, almost all phylogenetics studies based on nuclear and chloroplastic sequences have concluded that the bryophytes form a monophyletic group.

[26][33][35] The favored model, based on amino acids phylogenies, indicates bryophytes as a monophyletic group:[25] vascular plants hornworts mosses liverworts Consistent with this view, compared to other living land plants, all three lineages lack vascular tissue containing lignin and branched sporophytes bearing multiple sporangia.

The prominence of the gametophyte in the life cycle is also a shared feature of the three bryophyte lineages (extant vascular plants are all sporophyte dominant).

However, this distinction is problematic, firstly because some of the earliest-diverging (but now extinct) non-bryophytes, such as the horneophytes, did not have true vascular tissue, and secondly because many mosses have well-developed water-conducting vessels.

[38][39] The contrast is shown in the cladogram below:[40] bryophytes "protracheophytes", such as Aglaophyton or Horneophyton tracheophytes or vascular plants There have probably been several different terrestrialization events, in which originally aquatic organisms colonized the land, just within the lineage of the Viridiplantae.

[42] Molecular phylogenetic studies conclude that bryophytes are the earliest diverging lineages of the extant land plants.

In hornworts and mosses, stomata provide gas exchange between the atmosphere and an internal intercellular space system.

In common with ferns and lycophytes, a thin layer of water is required on the surface of the plant to enable the movement of the flagellated sperm between gametophytes and the fertilization of an egg.

Depending on the specific plant texture, bryophytes have been shown to help improve the water retention and air space within soil.

[49] When Phythium sphagnum is sprinkled on the soil of germinating seeds, it inhibits growth of "damping off fungus" which would otherwise kill young seedlings.

Bryophytes' antibiotic properties and ability to retain water make them a useful packaging material for vegetables, flowers, and bulbs.