Eichler divided plant kingdom into two sub- kingdoms - cryptogamae and phanerogamae. All plants without flowers and seeds are included in the sub- kingdom cryptogamae whereas phanerogamae includes plants which bear flowers and seeds. Cryptogams are further classified into three divisions, j Thallophyta, Bryophyta and Pteridophyta. Spore bearing plants such as mosses and ferns belong j to cryptogams because instead of reproducing by flowers and seeds they reproduce by means of spores.