Bryophytes are all "land plants", including mosses, hornworts and liverworts, that are non-vascular. They have tissues and enclosed reproductive systems, but they lack vascular tissue that circulates liquids. They do not have flowers or produce seeds, reproducing via spores.
Image Above: Northern bog club moss is a species of concern in Montana.
Definition adapted from URL: http://en.wikipedia.org/wiki/Bryophyte
Image from URL: http://en.wikipedia.org/wiki/File:Lycopodiella_inundata_161207.jpg