Long Live the Mycophycophyta!

I bet you have no idea what that word means, but don’t worry, I’m getting there. Mycophycophyta is the phylum name for Lichens. Since I took a Fungi course last fall, I thought I would elaborate on some interesting points I learned about lichens, since they really are pretty cool. Lichens, in case you were not aware, are a mutualistic symbioses between a fungus and either an algae species or a species of cyanobacteria. The fungus brings in the water and minerals, while the algae/cyanobacteria brings home the carbon compounds. Most lichens are 95% fungus, so the fungus gets to be boss and determine the shape of the organism. There are classifications based on shape, but we won’t get into that here, since that is not interesting to most people. However, lichens do not have any roots or absorptive organs, and live without soil, so they are dependent on rain for nutrients. This makes them very sensitive to pollution; so if you see them in an area, it is a good indicator of clean air.

Now for some interesting facts:


- Usnea fillipendula (“fishbone beard lichen”) contains usnic acid, which is a natural antibiotic. It has been used since ancient times throughout the world as a remedy.
- Cladinas are the lichens you see used for shrubbery on your grandfather’s train set.
- Parmelia omphalodes and P. saxatilis have been used by the Scots, Irish, and Laplanders to make dye. However, lichens only grow 1-10 mm a year, so these species tend to quickly become rare, and synthetic dyes are more commonly used now.
- Litmus paper is made from lichen.
- Due to the slow growth rate of lichens, they have been used to date rock surfaces (such as cracks caused by faults and shifting bedrock). Lichens have also been used to date surfaces when carbon dating fails. A minimum date is determined using the diameter of the largest lichen at a site. For more, see: Armstrong, R.A. (2004). Lichens, Lichenometry and Global Warming. Microbiologist, 9: 32-35.
- Lichens are also being explored as a natural alternative for herbicides and pesticides. Usnic acid, a product of some lichens, inhibits cartenoid synthesis, which bleaches the leaves of some plants (this results in a decline in chlorophylls and carotenoids). Synthetically created versions have already been used in creating herbicides. Other lichen products, such as depsides, barbatic acid, and lecanorin, act as PSII inhibiting herbicides, through the interruption of photosynthetic electron transport in chloroplasts. For more information, see: Becker 2001 and Dayan and Romagni 2001.
- Lichens are not poisonous, and can be considered ‘edible’, if, say, you are hopelessly lost in the woods and out of food; or dropped out of a helicopter by aliens with no supplies and have no idea what any of the plants around you are (and don’t go by what the animals are eating; their digestive systems are different than ours).