The name
Cryptogamae () means "hidden reproduction", meaning non-seed bearing plants. Other names, such as "
thallophytes", "
lower plants", and "spore plants" have occasionally been used. As a group, Cryptogamae are paired with the
Phanerogamae or Spermatophyta, the
seed plants. At one time, the cryptogams were formally recognised as a group within the plant kingdom. In his system for classification of all known plants and animals,
Carl Linnaeus (1707–1778) divided the plant kingdom into 24
classes, one of which was the "Cryptogamia". This included all plants with
concealed reproductive organs. He divided Cryptogamia into four orders:
Algae, Musci (
bryophytes), Filices (
ferns), and
fungi, but it had also traditionally included
slime molds, and
Cyanophyta. The classification is now deprecated in
Linnaean taxonomy. Cryptogams have been classified into three sub-kingdoms:
Thallophyta,
Bryophyta, and
Pteridophyta. Not all cryptogams are treated as part of the
plant kingdom today; the fungi, in particular, are a separate kingdom, more closely related to
animals than plants, while
blue-green algae are a
phylum of
bacteria. Therefore, in contemporary
plant systematics, "Cryptogamae" is not a taxonomically coherent group, but is
polyphyletic. However, the names of all cryptogams are regulated by the
International Code of Nomenclature for algae, fungi, and plants. == In human culture ==