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 converg ...

group of non-motile

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

s traditionally described as "thalloid plants", "relatively simple plants" or "

lower plants Non-vascular plants are plants without a vascular system consisting of xylem and phloem. Instead, they may possess simpler tissues that have specialized functions for the internal transport of water. Non-vascular plants include two distantly rel ...

". 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 photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...

ae that include

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

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 in ...

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 among ...

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 mu ...

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 t ...

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

thalloid Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms were ...

, 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 ...

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 "

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. Bio ...

, 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 ...

botanist Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...

, 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 siste ...

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

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

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

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.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

See also

References

Bibliography