thallus

noun, plural thal·li [thal-ahy] /ˈθæl aɪ/, thal·lus·es. Botany, Mycology.

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

noun plural thalli (ˈθælaɪ) or thalluses

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

n.Latin, from Greek thallos “green shoot, twig,” related to thalia “abundance,” thalos “scion, child,” ultimately from PIE root *dhal- “to bloom” (cf. Old Irish duilesc, a type of algae). n. pl. thal•lus•es

1. A plant body or fungus undifferentiated into stem, root, or leaf.

Plural thalli (thăl′ī)

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.