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

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Etymology

Origin of thallus

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

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Example Sentences

See Examples For:

thallus thalli

A slender stalk extends from the thallus, and an archegonial head sits at its top.

From Textbooks ● Jan. 1, 2015

Photosynthetic cells in the thallus contain a single chloroplast.

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 base of the hornwort plant, called the thallus, has a wrinkled, leaf-like appearance.

From Textbooks ● Jan. 1, 2015

Dictyota dichotoma, with a delicate, flattened, repeatedly forked thallus, is not uncommon in sandy pools on our coasts.

From The New Gresham Encyclopedia Volume 4, Part 1: Deposition to Eberswalde 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

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

From Textbooks ● Jan. 1, 2015

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

From Textbooks ● Jan. 1, 2015

These structures cannot then be produced from the product of a single spore nor even from the thalli derived from any two spores.

From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" by Various

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