Medulla

Definition

The medulla is the innermost layer of a lichen's thallus, consisting of loosely packed fungal hyphae. It plays a crucial role in nutrient storage and water retention.

5 Must Know Facts For Your Next Test

1. The medulla is primarily composed of fungal hyphae.
2. It is located beneath the photobiont layer in lichens.
3. The medulla contributes to the structural integrity of the lichen thallus.
4. It aids in the storage of nutrients and water for the lichen.
5. In some lichens, it can also contain crystals or other inclusions.

Review Questions

• What is the primary composition of the medulla in lichens?
• Where is the medulla located within a lichen's thallus?
• How does the medulla contribute to a lichen’s survival?

Related terms

Thallus:

The body of a lichen, consisting of layers including the cortex, photobiont layer, and medulla.

Hyphae:

Thread-like structures that make up the mycelium of fungi and are found in various layers of lichens.

Photobiont Layer: The layer in a lichen where photosynthetic algae or cyanobacteria reside, providing nutrients through photosynthesis.