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common name for members of the Thallophyta (or Thallobionta), a taxonomic group in some archaic classification systems that comprised algaealgae
[plural of Lat. alga=seaweed], a large and diverse group of primarily aquatic plantlike organisms. These organisms were previously classified as a primitive subkingdom of the plant kingdom, the thallophytes (plants that lack true roots, stems, leaves, and flowers).
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, fungiFungi
, kingdom of heterotrophic single-celled, multinucleated, or multicellular organisms, including yeasts, molds, and mushrooms. The organisms live as parasites, symbionts, or saprobes (see saprophyte).
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, and lichenslichen
, usually slow-growing organism of simple structure, composed of fungi (see Fungi) and photosynthetic green algae or cyanobacteria living together in a symbiotic relationship and resulting in a structure that resembles neither constituent.
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. The thallophytes were considered lower plantsplant,
any organism of the plant kingdom, as opposed to one of the animal kingdom or of the kingdoms Fungi, Protista, or Monera in the five-kingdom system of classification.
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 and were grouped together because of they consisted of one cell or a relatively undifferentiated mass of cells called a thallus, instead of having an organized plant body (stem, root, and leaf).
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a lower plant (an alga, fungus, or lichen) whose body is not divided into stem and leaves but consists of a thallus. (A plant whose body is divided into stem and leaves is a cormophyte.) Some algae, for example, Caulerpa, Macrocystis, and Sargassum, are externally differentiated into stem and leaf organs, but the anatomic structure of these organs is less complex than in higher plants.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The thallophyte communities growing on both natural and artificial rock surfaces are well defined often species-rich.
The thallophyte syntaxa of bryophytes, lichens and algae have been compiled for the first Europe-wide checklist of high ranked syntaxa including the bryophyte, lichen and algal syntaxa (EuroVegChecklist: MUCINA & al., in press).
Table 1 Classes of the thallophyte syntaxa, contributors (B: bryophytes, L: lichens, A: algae & cyanobacteria) and their habitat type (Cladonio-Lepidozietea and Desmococcetea olivacei are listed twice).
In an obituary of Pringsheim, Scott (1895) championed Pringsheim's opinion that the free-living sexual and asexual forms of thallophytes were homologous, and that their alternation was the phylogenetic precursor to the alternation of gametophytic and sporophytic generations in archegoniates.
The homologous theory got rid of the need to intercalate a new generation and required only the modification of the already existing sexual and asexual forms of thallophytes. Scott wrote "There is no reason to believe that the Bryophyta, as we know them, were the precursors of the vascular Cryptogams at all....