(a) : Algae, bryophyte and pteridophyte are cryptogams, but out of them algae, and bryophytes are lower cryptogams and do not possess vascular tissue (xylem and phloem), whereas in pteridophytes, vascular tissue system is well developed and so these are higher cryptogams or vascular cryptogams. The term cryptogams means that these plants reproduce by means of spores and do not produce seeds. The vascular tissue of pteridophytes is well developed. They contain both xylem and phloem. In xylem, vessels are absent and in phloem companion cells are absent. So pteridophytes or vascular cryptogams are a group of seedless vascular plants, that have successfully invaded the land and reproduce by means of spores. Gymnosperms are naked seed bearing plants called phanerogams.