homoeomerous thallus

A thallus is the plant body of organisms like algae and fungi, lacking the specialized tissues (stems, leaves) of higher plants. In lichens, the thallus is a symbiotic composite body formed by algae or cyanobacteria and fungi.12

There are two main classifications of lichen thalli based on the ratio of algal to fungal cells:
* Homoeomerous thallus: Algal cells are distributed throughout the structure and are more numerous than fungal cells.32
* Heteromerous thallus: This is the more common type, characterized by a predominance of fungal cells arranged in distinct layers.32

Lichens can reproduce vegetatively, with portions of the thallus breaking off to form new growth. Some lichens also form specialized structures like soredia or isidia for asexual propagation.23