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thallus Line breaks: thal|lus
Pronunciation: /ˈθaləs/

Definition of thallus in English:

noun (plural thalli ˈθalʌɪˈθaliː)

A plant body that is not differentiated into stem and leaves and lacks true roots and a vascular system. Thalli are typical of algae, fungi, lichens, and some liverworts.
Example sentences
  • Oomycetes resemble fungi in the form of their thalli, ecology, and the plant parasitic ability of some species and are traditionally studied by mycologists.
  • Some causal relationships between morphology and hydrodynamic performance have been established for macroalgae, through theoretical studies and hydrodynamic comparisons of differently exposed thalli.
  • Ceratopteris spores, like fucoid zygotes, divide unequally to produce a small rhizoid cell and a larger cell that develops into the thallus.


Example sentences
  • Furthermore, logs provide persistent, exposed substrate where thalloid gametophytes can escape smothering by deciduous hardwood leaf litter.
  • Ultrastructural research has revealed that the placental organization is remarkably diverse between major bryophyte groups but that, with the exception of simple thalloid liverworts, it shows only minor intra-group variation.
  • When a spore germinates, it produces a flat thalloid plant with a greasy blue-green color and odd morphology.


Early 19th century: from Greek thallos 'green shoot', from thallein 'to bloom'.

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