Lichens are a type of composite organism created when algae and/or cyanobacteria form a symbiotic relationship with fungi.

Although some features of lichen are plant-like, they are unique from fungi and plants. The algae and/or cyanobacteria portion of lichens produce food from photosynthesis; the fungus portion of the lichen provides an anchor for the organism as well as gathers minerals and water from the surrounding environment. Lichens grow in a wide variety of environmental conditions and are generally organized by the growth structure they display.

Click here to learn some basic terms that will help you identify lichens and their parts.

Lichens come in these  5 “structure types”:


Foliose category
Foliose lichens grow somewhat flatly against the substrate, appearing “foliage-like” or “leafy” around the edges. They also have a distinct underside unlike “crustose” lichens.


"Tendrils" are long, slender, fleshy structures that grow in the form of inert tentacles.
Growing out from one single point upon its substrate, “Fruticose Lichens” can be seen as tufted OR hanging “tendrils” coming in many different shapes or sizes

These types below aren’t generally harvested due to their delicate structure types:


   Grows like a “crust” tightly against the substrate (usually rock or wood)


thallus consisting of minute, scale-like “squabbles”


thallus consists of powdery growth across surface of substrate

Other Types of Lichen growth structures include:


thallus structure is jelly-like


thallus is stringy or like matted hair


thallus has a wispy structure (somewhat like teased wool)


having no consistent growth structure or characteristics

 Regarding Lichens & ‘Positive-Impact Harvesting Techniques’:

Lichen can be very sensitive to air pollution, & are surprisingly precise air quality monitors!     Because of this, they often grow sparsely in urban areas.

Traditionally people have used lichen for a variety of reasons, including as medicine, food and dyes.

As per harvesting:

After consulting lichen experts in Canaca, U.S.A., U.K., & Australia, Karen Diadick Casselman in her book Lichen Dyes, The New Source Book developed a code of ethics for collecting lichens with the intended use of dying fiber.

  • Learn about lichens in your region— reproduction/dispersal, ecology, habitat issues, conservation issues
  • Learn to identify lichens before collecting
  • Collect primarily salvage material—lichens that have blown out of trees or other situations where the lichens would otherwise be destroyed (i.e. on firewood, lichens growing on roofs or structures that will be cleaned)
  • Use only those lichens that are conspicuously abundant
  • Collect no more than 10% of the material from the area you are collecting in
  • Do not buy or sell lichens
  • Do not collect in parks, historic sites, or protected areas
  • Do not use lichen dyes for large textile projects that require more than 6-7 lbs of yarn
  • Do not use lichen for dyes that result in colors that are easily obtained naturally or from other dye sources (e.g. beige)
  • Avoid group collecting and set a good example by your own collecting methods

These guidelines have also been recommended by The California Lichen Society, who has a section on using lichens for dyes HERE.


Bibliography:,, “Lichen Dyes, The New Source Book” by Karen Diadick Casselman, California Lichen Societywordpress.orgThe Free Dictionary by FARLEX,  “Explanatory Dictionary” plugin by WordPress

Photos & Database Entry:  Distance Everheart 12-29-13, updated 11-28-2015 by Ender Kirin

2 thoughts on “Lichen:”

  1. I wanted to make a quick message to express gratitude to you for all of the awesome steps you are writing on this website. My extended internet look up has finally been rewarded with really good insight to write about with my classmates and friends. I ‘d suppose that many of us visitors are undoubtedly fortunate to dwell in a really good network with very many wonderful professionals with good guidelines. I feel somewhat grateful to have used your site and look forward to so many more entertaining moments reading here. Thanks once more for everything.

Leave a Reply

Your email address will not be published. Required fields are marked *