What is the Difference Between Fungi and Lichen

The key difference between fungi and lichen is that fungi are simple heterotrophic organisms while lichen is a composite symbiotic organism that forms from algae or cyanobacteria living among filaments of multiple fungi species.

The natural ecosystem is made up of countless organisms. Some of them are invisible to the naked eyes, while others are visible. Flora and fauna in an ecosystem are very complex as they contain billions of organisms. All these organisms are a part of an ecosystem and participate in it. An ecosystem comprises autotrophs that make their own food and heterotrophs that depend on others to obtain food. Sometimes, an ecosystem also has organisms that live together in a relationship with each other such as parasitic, symbiotic, or mutualistic organisms. Therefore, fungi and lichens are very important distinct organisms that are living in natural ecosystems.


1. Overview and Key Difference
2. What is Fungi 
3. What is Lichen
4. Similarities – Fungi and Lichen
5. Fungi vs Lichen in Tabular Form
6. Summary

What is Fungi?

Fungi are simple heterotrophic organisms. Heterotrophs are those organisms that cannot make their own food. Therefore, fungi depend on others to obtain foods. They are single-celled or multicellular. Fungi are eukaryotic in nature. These fungi are extremely important for the smooth functioning of an ecosystem. The study of fungi is termed mycology. Most importantly, fungi can reproduce both sexually and asexually. There are about 144,000 known species of organisms belonging to the kingdom fungi. Kingdom fungi include yeast, rusts, smuts, mildews, molds, and mushrooms. However, there are fungi-like organisms such as slime molds and oomycetes (water molds) that are often called fungi but do not belong to this kingdom.

Figure 01: Fungi

Fungi are subdivided into three groups based on their life cycle, the structure of the fruiting body, and the type of spore they produce: multicellular filamentous molds, macroscopic filamentous fungi that form large fruiting bodies (mushrooms), and single-celled microscopic yeasts. The cell walls of fungi are made up of chitin, which is a hard substance usually in the exoskeletons of insects. Furthermore, fungi use filament-like structures to obtain their food. These organisms can survive in most environmental conditions. Fungi can even obtain their food from dead or decaying matter.  This is the reason why fungi are essential to the natural ecosystem.

What is Lichen?

Lichen is a composite symbiotic organism that forms from algae or cyanobacteria living among filaments of multiple fungi species. Lichen is, therefore, a symbiosis between fungi and algae or fungi and cyanobacteria. It is a very complex organism. Fungi are the dominant partners that give lichens most of their characteristics. In lichen, fungi provide the stable condition on which the algae or cyanobacteria can grow on land. The algae or cyanobacteria, in turn, provides the simple sugar (food) generated from photosynthesis to the fungi.

Figure 02: Lichen

Lichen can be found in a variety of habitats like on tree barks, rocks, walls, etc. Lichen is very important to the ecosystem because it can convert carbon dioxide in the atmosphere into oxygen through photosynthesis. Lichen is also very beneficial for humans as they can absorb any atmospheric pollutants such as heavy metal, carbon, or sulphur.

What are the Similarities Between Fungi and Lichen?

  • Fungi and lichen are very important organisms living in natural ecosystems.
  • Fungi and lichen are both helpful in reducing the environmental pollution.
  • Both have heterotrophic species.
  • These organisms can live on similar habitats such as trees barks, rocks, walls, etc.

What is the Difference Between Fungi and Lichen?

Fungi are simple heterotrophic organisms, while lichen is a composite symbiotic organism that forms from algae or cyanobacteria living among filaments of multiple fungi species. So, this is the key difference between fungi and lichen. Furthermore, fungi usually grow in shady, dark, and moist places, while lichen usually grows freely in places that expose to air and light.

The following infographic lists the differences between fungi and lichen in tabular form for side by side comparison.

Summary – Fungi vs Lichen

Fungi are heterotrophic in nature. They are eukaryotes. Fungi often can form a symbiotic relationship with green algae or cyanobacteria to produce lichen. In lichens, fungi protect algae or cyanobacteria, while algae or cyanobacteria provide food for fungi through photosynthesis. Thus, this summarizes the difference between fungi and lichen.