CSIRO ScienceImage 4092 Lichen on tree in Adelaide Hills SA 1992

Thallophytes (Thallophyta, Thallophyto or Thallobionta) are a

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

group of non-motile

organism In biology, an organism () is any life, living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy (biology), taxonomy into groups such as Multicellular o ...

s traditionally described as "thalloid plants", "relatively simple plants" or " lower plants". They form a

division Division or divider may refer to: Mathematics *Division (mathematics), the inverse of multiplication *Division algorithm, a method for computing the result of mathematical division Military * Division (military), a formation typically consisting ...

of kingdom

Plant Plants are predominantly Photosynthesis, photosynthetic eukaryotes of the Kingdom (biology), kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all curr ...

ae that include lichens and

algae Algae ( , ; : alga ) are any of a large and diverse group of photosynthetic, eukaryotic organisms. The name is an informal term for a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from ...

and occasionally

bryophyte The Bryophyta s.l. are a proposed taxonomic division containing three groups of non-vascular land plants ( embryophytes): the liverworts, hornworts and mosses. Bryophyta s.s. consists of the mosses only. They are characteristically limited ...

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

and

slime mould Slime mold or slime mould is an informal name given to several kinds of unrelated eukaryotic organisms with a life cycle that includes a free-living single-celled stage and the formation of spores. Spores are often produced in macroscopic mul ...

s. Thallophytes have a hidden reproductive system and hence they are also incorporated into the similar

Cryptogam A cryptogam (scientific name Cryptogamae) is a plant (in the wide sense of the word) or a plant-like organism that reproduces by spores, without flowers or seeds. The name ''Cryptogamae'' () means "hidden reproduction", referring to the fact ...

ae category (together with

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes except ...

s), as opposed to Phanerogamae. Thallophytes are defined by having undifferentiated bodies ( thalloid, pseudotissue), as opposed to

cormophyte Cormophytes (Cormophyta) are the "plants differentiated into roots, shoots and leaves, and well adapted for life on land, comprising pteridophytes and the Spermatophyta." This group of plants include mosses, ferns and seed plants. These plants dif ...

s (Cormophyta) with roots and stems. Various groups of thallophytes are major contributors to marine ecosystems.

Definitions

Several different definitions of the group have been used. Thallophytes (Thallophyta or Thallobionta) are a polyphyletic group of non-mobile organisms traditionally described as "thalloid plants", "relatively simple plants" or " lower plants".

Stephan Endlicher Stephan Ladislaus Endlicher also known as Endlicher István László (24 June 1804, Bratislava (Pozsony) – 28 March 1849, Vienna) was an Austrian botanist, numismatist and Sinologist. He was a director of the Botanical Garden of Vienna. ...

, a 19th-century

Austria Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...

n botanist, separated the vegetable kingdom into the thallophytes (algae, lichens, fungi) and the cormophytes (including

s and thus being equivalent to

Embryophyta The Embryophyta (), or land plants, are the most familiar group of green plants that comprise vegetation on Earth. Embryophytes () have a common ancestor with green algae, having emerged within the Phragmoplastophyta clade of green algae as sis ...

in this case) in 1836. This definition of Thallophyta is approximately equivalent to Protophyta, which has always been a loosely defined group. In the

Lindley system An early system of plant taxonomy, the Lindley system, was first published by John Lindley as ''An Introduction to the Natural System of Botany'' (''Natural History'', 1830). This was a minor modification of that of de Candolle (1813). He develop ...

(1830–1839), Endlicher's cormophytes were divided into the thallogens (including the bryophytes), and cormogens ("non-flowering" plants with roots), as well as the six other classes. Cormogens were a much smaller group than Endlicher's cormophytes, including just the ferns (and

Equisetopsida Equisetidae is one of the four subclasses of Polypodiopsida (ferns), a group of vascular plants with a fossil record going back to the Devonian. They are commonly known as horsetails. They typically grow in wet areas, with whorls of needle-like ...

) and the plants now known as

lycopodiophytes The lycophytes, when broadly circumscribed, are a vascular plant (tracheophyte) subgroup of the kingdom Plantae. They are sometimes placed in a division Lycopodiophyta or Lycophyta or in a subdivision Lycopodiophytina. They are one of the oldest ...

. Thallophyta is a division of the plant kingdom including primitive forms of plant life showing a simple plant body. Including unicellular to large

fungi A fungus (plural, : fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeasts and Mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified ...

, lichens. The first ten phyla are referred to as thallophytes. They are simple plants without roots stems or leaves.Robbins, W.W., Weier, T.E. and Stocking, C.R. 1959. ''Botany an Introduction to Plant Science.'' Chapman & Hall, Limited, Limited They are non-embryophyta. These plants grow mainly in water.

Subdivisions

The Thallophyta have been divided into two subdivisions: * Myxothallophyta (myxomycetes) * Euthallophyta (bacteria, fungi, lichens, algae) The term Euthallophyta was originally used by

Adolf Engler Heinrich Gustav Adolf Engler (25 March 1844 – 10 October 1930) was a German botanist. He is notable for his work on plant taxonomy and phytogeography, such as ''Die natürlichen Pflanzenfamilien'' (''The Natural Plant Families''), edited with ...

References

Bibliography

* * * {{Protist structures Cryptogams Historically recognized plant taxa

Definitions

Subdivisions

See also

References

Bibliography