Bryophytes are  embryophtes (land plants) without vascular tissue.  Though some bryophytes  have specialized tissues for the transport of water, they do not contain lignin and are therefore not considered to be true vascular tissue. Bryophytes produce enclosed reproductive structures (gametangia and sporangia), however they do not produce flowers or seeds, instead reproducing by spores. This group includes mosses, hornworts, and liverworts.