thallusstructuur

Thallusstructuur refers to the vegetative body of certain organisms, primarily algae, fungi, lichens, and some liverworts and hornworts, that is not differentiated into true roots, stems, and leaves. This undifferentiated structure is called a thallus. The complexity of thallus structure can vary significantly. In its simplest form, a thallus might be unicellular or a simple colony of cells. More complex thalli can be multicellular and exhibit some degree of organization, though lacking the specialized tissues found in vascular plants.

Algae display a wide range of thallus forms. Some are microscopic and unicellular, while others form filamentous, sheet-like, or branched structures. Macroscopic algae, such as kelps, can have impressively complex thalli that may superficially resemble leaves (phylloids), stems (cauloids), and root-like holdfasts, but these structures do not possess the same anatomical and functional differentiation as their counterparts in vascular plants.

In fungi, the thallus is typically referred to as a mycelium, which is a network of branching hyphae. Lichens, which are symbiotic organisms composed of a fungus and an alga or cyanobacterium, also possess thalli. These lichen thalli can be crustose (crust-like), foliose (leaf-like), or fruticose (shrubby or hanging). The specific morphology and organization of the thallus are important characteristics used in the classification and identification of these organisms. The term thallus emphasizes a simpler, less differentiated body plan compared to the more complex sporophyte generation of land plants.