noun one of a large class or division of the vegetable kingdom, which includes those flowerless plants, such as fungi, algae, and lichens, that consist of a thallus only, composed of cellular tissue, or of a congeries of cells, or even of separate cells, and never show a distinction into root, stem, and leaf.
THALLOGEN
Meaning of THALLOGEN in English
Webster English vocab. Английский словарь Webster. 2012