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

• thalloid
  adjective

Etymology

Origin of thallus

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

Example Sentences

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

From Textbooks • Jan. 1, 2015

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

From Textbooks • Jan. 1, 2015

The spores sprout, producing a new thallus and rhizoids.

From Textbooks • Jan. 1, 2015

In a bryophyte, all the conspicuous vegetative organs—including the photosynthetic leaf-like structures, the thallus, stem, and the rhizoid that anchors the plant to its substrate—belong to the haploid organism or gametophyte.

From Textbooks • Jan. 1, 2015

Thall′ōme, a thallus; Tham′nium, the branched shrub-like thallus of fruticulose lichens.

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