thallus

American  

[thal-uhs] / ˈθæl əs /

noun

Botany, Mycology.

plural

thalli, thalluses

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

---

thallus British  

/ ˈθæləs /

noun

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

---

thallus Scientific  

/ thăl′əs /

plural

thalli

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.

---

Other Word Forms

• thalloid adjective

Etymology

Origin of thallus

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

Example Sentences

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

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

Photosynthetic cells in the thallus contain a single chloroplast.

From Textbooks • Jan. 1, 2015

External enzymes digest nutrients that are absorbed by the body of the fungus called a thallus.

From Textbooks • Apr. 25, 2013

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