Thallus

Definition

Thallus is the undifferentiated vegetative tissue of some organisms, including fungi, algae, and lichens. It lacks true stems, roots, or leaves.

5 Must Know Facts For Your Next Test

1. Thalli are typically flat and can be either unicellular or multicellular.
2. In fungi, the thallus forms the main body structure of molds and mushrooms.
3. Lichens consist of a symbiotic association between a fungus and an alga or cyanobacterium, both contributing to the thallus structure.
4. The thallus in algae functions similarly to plant leaves in photosynthesis but lacks complex vascular tissues.
5. Reproduction in organisms with a thallus can occur through spores or fragmentation.

Review Questions

• What is a thallus and what key characteristics does it lack?
• How does the thallus function differently in fungi compared to algae?
• Describe how lichens utilize the concept of a thallus for their structure.

Related terms

Hyphae:

The filamentous structures that make up the mycelium of a fungus.

Mycelium: The network of hyphae that forms the vegetative part of a fungus.

Photosynthesis: The process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.