thallus
nounUK /ˈθæləs/
US /ˈθæləs/
A plant body that has no real leaves, stems, or roots.
The seaweed's thallus spread flat across the wet rocks.
OTHER MEANINGS
2. The flat, leaf-like body of a seaweed or alga.
Each thallus of the kelp was long and ribbon-like.
3. The simple body of a lichen, made of fungus and alga together.
The lichen's thallus clung tightly to the bark.
4. A plant-like growth in fungi that lacks true roots and stems.
Under the microscope, the fungal thallus looked like a tangle of threads.