Short answers, pulled from the story.
Bryophytes are non-vascular land plants comprising about 20,000 species divided into three lineages: liverworts (Marchantiophyta), mosses (Bryophyta), and hornworts (Anthocerotophyta). They lack true vascular tissue containing lignin and do not produce flowers or seeds. They reproduce sexually by spores and asexually by fragmentation or the production of gemmae.
Land plants, including the bryophyte lineages, emerged within the green algae between 510 and 630 million years ago. Molecular phylogenetic studies identify bryophytes as the earliest diverging lineages among all extant land plants, making them key evidence for the transition from aquatic to terrestrial life.
In bryophytes, the haploid gametophyte is the more prominent and longer-lived stage of the life cycle. The diploid sporophyte appears only occasionally, remains physically attached to the gametophyte, and depends on it for nutrition throughout its life. This contrasts with vascular plants, which are sporophyte dominant.
The term Bryophyta was first suggested by Braun in 1864. German bryologist Wilhelm Schimper used it in 1879 to describe a group containing all three bryophyte clades, though at that time hornworts were considered part of the liverworts rather than a separate lineage.
Almost all recent phylogenetic studies based on nuclear and chloroplastic sequences support bryophyte monophyly. A 2014 study argued that earlier phylogenies built on nucleic acid sequences were subject to composition biases, and that amino acid-based phylogenies support the single common ancestor model. Phylogenies based on mitochondrial sequences remain an exception and do not support the monophyletic view.
Sphagnum moss was used as surgical wound dressing in World War I for its antiseptic and water-retaining properties. Peat, a fuel derived primarily from dried Sphagnum, is a major commercial product. Bryophytes are also used as packaging for flowers and bulbs, as environmental pollution indicators, and some species produce natural pesticides; the liverwort Plagiochila produces a chemical poisonous to mice.