thallus

American  

[thal-uhs] / ˈθæl əs /

noun

Botany, Mycology.

• thalli,
  plural
• thalluses
  plural

1. a simple vegetative body undifferentiated into true leaves, stem, and root, ranging from an aggregation of filaments to a complex plantlike form.

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thallus British  

/ ˈθæləs /

noun

1. the undifferentiated vegetative body of algae, fungi, and lichens

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thallus Scientific  

/ thăl′əs /

• thalli
  plural

1. A type of body found among plants and fungi that is not differentiated into roots, stems, or leaves. Thalli are found among lichens, mosses, liverworts, and many algae, as well as the gametophyte generations of horsetails and ferns, which have rhizoids but not true roots.

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Other Word Forms

Derived Forms

• thalloid
  adjective

Inflected Forms

Nouns

• thalli
  plural
• thalluses
  plural

Etymology

Origin of thallus

1820–30; < New Latin < Greek thallós young shoot, twig

Example Sentences

See Examples For:

thallus thalli

Root-like rhizoids grow from the bottom of the thallus.

From Textbooks ● Jan. 1, 2015

Large cells form the thallus: the main stem of the alga.

From Textbooks ● Jan. 1, 2015

The thallus of lichens grows very slowly, expanding its diameter a few millimeters per year.

From Textbooks ● Jan. 1, 2015

The body of a lichen, referred to as a thallus, is formed of hyphae wrapped around the green partner.

From Textbooks ● Apr. 25, 2013

Sporol′ogist, a botanist who emphasises the spores in classification; Spō′rophore, the part of the thallus which bears spores: the placenta in flowering plants: a sporophyte.—adjs.

From Chambers's Twentieth Century Dictionary (part 4 of 4: S-Z and supplements) by Various

Fruticose lichens have thalli that are branch-, cup- or club-like, imparting the look of tiny shrubs.

From Seattle Times ● Nov. 22, 2021

Foliose species have lobed, leaflike bodies, or thalli; you can see both their upper and lower surfaces, which are different colors.

From Seattle Times ● Nov. 22, 2021

Spores disseminated by wind or water germinate into flattened thalli attached to the substrate by thin, single-celled filaments.

From Textbooks ● Jan. 1, 2015

The gametophytes grow as flat thalli on the soil with embedded gametangia.

From Textbooks ● Jan. 1, 2015

Other algae doubtless sometimes occur in the thalli of Peltigerae.

From Ohio Biological Survey, Bull. 10, Vol. 11, No. 6 The Ascomycetes of Ohio IV and V by Leafy Jane Corrington Hilker