Mushrooms growing from a dead tree in the Sourlands.

Writing a brief essay on fungi is daunting because it is such a vast subject.  It is vast in terms of its size—there are about ten times more fungal species in the world than plant species, but the fungal world is so unknown that estimates for the number of species range from 2.2 million to 3.8 million.  The fungi world is also vast in terms of its diversity.  Fungi nourish, protect and kill plants; they nourish and kill humans and many other animals; they can influence behavior in many animal species and cause hallucinations in humans; they make soil by decomposing organic material and by eroding rocks (as part of lichens); they are used to make medicines and detergents; they can restore to productivity sites that have been left so devastated by human abuse that they cannot support plants.

Fungi can be found everywhere.  They are in the deepest ocean valleys.  They are in icy crevasses in Antarctica.   They are in deserts.  Virtually every plant on earth contains fungi. The yeasts in our gut as well as those that cause fermentation or bread dough to rise, are fungi; so is the mold on a too-old peach. They are abundant in soils, especially forest soils, where it is estimated that a teaspoon of soil contains 100 yards or more of fungal threads.

Most fungi are formed from networks of long, filamentous tubular structures called hyphae that branch, fuse and tangle into chaotic filigrees called mycelium. The hyphae are about one five-hundredth of an inch thick so they are visible only with a microscope. Hyphae grow from their tips, penetrating between the cells of living or dead organic material.  Their growth is in response to environmental stimuli.  From a great distance hyphae can detect and grow toward other hyphae that are sexually compatible.  They are also able to navigate mazes by sending hyphae in all directions and then strengthening one that successfully navigates the maze, while allowing others to atrophy.

One type of fungi, mycorrizal, has developed a symbiotic relationship with plants, growing into their roots.  This fungus obtains glucose from plants, and in exchange provides plants with water and minerals.  Plant roots can obtain water and minerals from the soil on their own, but the mycorrizal fungi’s hyphae are much more efficient because they are 50 times thinner than the hairs on plant roots and can be up to 100 times longer.  Ninety percent of all plants are connected to mycorrizal fungi.  I have read arguments that there would be no plant life on earth if it were not for mycorrizal fungi, and no plant life would mean no animal life.  

The symbiotic relationship between mycorrizal fungi and plants is complicated.  Any plant is likely to have more than one of them connected to its roots and any one mycorrizal fungi is likely to be connected to more than one plant.  Further, the exchange between the fungi and the plants is also complex.  Fungi sometimes transfer the glucose that it takes from one plant and deliver it to another plant.  The fungi also transmit information from one plant to another, probably chemically. When aphids attack some plants they will release a chemical that attracts an aphid-eating wasp. Other plants, connected to the signaling plant through the mycorrizal network, also release the wasp-attracting chemical, even though they are not attacked themselves. Scientists have dubbed this network the “wood wide web.”  This quality of connecting plants and facilitating the exchange between the plants of nourishment and chemical signals causes some scientist to begin speculating about plants willfully helping each other and even having the “desire” to donate food to plants that are young or somehow deprived of adequate nourishment.

If people eat psilocybin mushrooms they will experience hallucinations.  Much remains to be known about these mushrooms and their effect on people but we know that psilocybin mushrooms sometimes play a significant role in religion and medicine.  Religious practices of many people in Central and South America depend on eating psilocybin mushrooms.  Many North Americans who have experienced these mushroom-induced hallucinations tell about exalted feelings of joy and bliss and a sense of “oneness” during their “trips.”  Oneness, a sense that the universe is whole and we are all part of it, that there is no boundary to time or space, is central to Christianity and many other major religions. 

What an incredibly complicated form of life!  Fungi are everywhere and can do everything.  They have always been part of life on earth and they appear to be indestructible.

 Jack-o-Lantern mushrooms growing on an old stump in the Sourlands.  If you eat these delicious-looking mushrooms you will not die but you will be very, very sick.