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Neglected natives help your garden thrive and more
By Lucy Warren
Lovely Oak woodland dweller. Blewits (Lepista nuda) are regarded as one of the most beautiful mushrooms in San Diego County. They are also prized for their delicate flavor.
Photo: Paul Maschka
Mushrooms are an acquired taste, complex earthy and delicate, yet always a little mysterious. Seldom the principle culinary ingredient, they usually perform their magic behind the scenes adding depth and richness. In addition to their elegance, fungi have the capability of striking fear, for some can be fatal, just as others provide compounds that can cure fatal diseases. But few of us are aware of the complexity of this fascinating botanical kingdom.
Over a decade ago when a good friend’s husband joined the San Diego Mycological Society, my eyes rolled back as I envisioned dreary scientists, ultimate plant nerds and over-the-top gardeners, mixed in with a few gourmets. Mycology literally means “fungus study.” I couldn’t imagine how people could focus on such a limited topic. But then again, when I was ten I couldn’t imagine how people could possibly eat or, ick, actually like caviar. Fortunately, I grew up and gained more appreciation for both.
Gardening books seldom, if ever, reference fungi. And, few gardeners purposefully propagate them (although this is changing a little). In fact, scientifically speaking, fungi dwell in their own organic kingdom. They share similarities with both the plant and animal kingdoms, but are distinctively different than both. And the kingdom is vast—it is estimated to include approximately 1.5 million separate species. Just think of the opportunity for cultivars!
Fungi arrived early in the evolution of living organisms. Like ferns, they propagate by spores, not seeds. Like animals, they do not produce their own food but rely on other organic sources. Unlike plants, they neither have vascular systems nor produce chlorophyll. As a result they can live in dark places, such as underground. Like plants, they can directly absorb minerals. Like microbes, they can live in extreme environments, but are adapted to specific ones.
One of earth’s earliest terrestrial life forms, lichen, is actually a symbiotic partnership of fungus and either algae or cyanobacteria. Ever so slowly lichen extract minerals from bare rock and synthesize them into plant-absorbable material that forms soil, making it available to support plant growth. And soil, as we all know, is the mixture of rock particles and organic material (usually with lots of bio-organisms mixed in).
Chicken of the woods (Laetiporus sulphureus) mushrooms are one of the first mushrooms to emerge in early fall well before our rainy season. They are also known as Sulfur shelf mushrooms. Their stunning yellow and pink coloration are hard to miss. Chicken of the woods are considered a parasite but they will continue blooming from a fallen tree for decades. Photo: Paul Maschka
Ecological Role of Fungi
Although largely invisible to all but a probing investigator, fungi play a huge role in the soil food web and are the alpha and omega of the food chain. They synthesize organic material, which becomes progressively available to larger and larger organisms, until each dies and again becomes eligible for decomposition and re-absorption by the fungi and bacteria.
For the most part, like Rodney Dangerfield, the bacteria and fungi get no respect, yet without these important organisms working in the detritus of our lives, we would literally be in deep doo-doo. Organic decomposition is a major role of fungi in our environment. Along with bacteria, fungi recycle carbon, nitrogen and essential mineral nutrients, that is, non-living organic material. These fungi work silently, from decomposing fallen trees to eating away at cowpies in meadows, even cleaning up toxic waste sites—including absorption of dangerous substances such as mercury.
Some fungi are parasitic, in that they may take advantage of a host organism for the parasite’s survival. These fungi need a host and most require a specific species or family. Usually they do not kill the host since they depend on it for their own survival, but by utilizing the host’s resources they may further weaken it. Every year fungus, such as rust, ruins billions of dollars of plant crops. The parasitic fungi invade plants and animals alike, from single-celled diatoms to animals and humans (yeast infections and athletes foot, as examples). As we look at these in a larger context, the parasitic role is also important in nature, for these fungi do not take hold in plants or animals with strong immune systems, but rather in those which have compromised immune systems. A healthy plant or animal will strike back and bombard the fungi with chemicals to ward off or minimize the invasion.
Then there are the symbiotic fungi that may invade or cohabitate with a host, enhancing the effectiveness and health of both. Picture a whole front yard full of mushrooms and fungi—not exactly a traditional landscape. Yet, if you are driving past a beautiful, well-designed and healthy California native landscape and look just a little deeper, that’s exactly what you will find!
Chicken of the woods (Laetiporus sulphureus) mushrooms are one of the first mushrooms to emerge in early fall well before our rainy season. They are also known as Sulfur shelf mushrooms. Their stunning yellow and pink coloration are hard to miss. Chicken of the woods are considered a parasite but they will continue blooming from a fallen tree for decades.
Turkey Tail (Trametes versicolor) mushrooms are common on fallen logs. They help break down the hard lignin cells in wood using powerful enzymes. Turkey tail mushrooms have been used for centuries in Asia as medicinal mushrooms. Photo: Paul Maschka
At the Root Level
Most of us have heard the expression, “feed the soil, not the plants.” Soil science has shifted away from the false wisdom of just throwing chemicals at plants to increase production. Current realization is that maintaining healthy soil is much more complex than adding a bag of 5-10-5 with a few micronutrients.
Garden soil full of healthy fungi and microorganisms contributes to healthy productive plants. It’s that simple. Not only are the decomposing-fungi working on recycling the organic material back into a rich usable form for higher life forms, but tiny fungus mycelia are working to increase the root area of the plants by 1,000 times! Each microscopic mycelium is more than 100 times smaller than a root hair.
The symbiosis of the mycelium of the fungus and the plant root is called mycorrhiza. The term comes from Latin: myco meaning fungus and rhiza meaning root. Interestingly, it is estimated that 90 percent of all plants have a micorrhizal symbiont.
In the past couple of decades, we have come to better understand the roles of these miniature powerhouses in creating healthy, productive landscapes. Millions of mycelia attached to the rootlets of a plant contribute to increasing availability of soil nutrients. Just as important in our dry climate, the mycelia are so small that they are capable of breaking through the surface tension of whatever tiny droplets of water are available in the soil. Enhanced hundreds of times beyond the actual surface of the root hair, this optimizes nutrient and water uptake, improving the vitality and survival of the plant.
Have you ever looked at the difference between a plowed field and an undisturbed native landscape area after a heavy storm? Far more soil washes away from the field. Joined together in virtual underground mats within the soil matrix, the micorrhiza hold the soil aggregates together and reduce erosion. Yes, this happens even after firestorms, as the micorrhiza are underground.
Even upscale nurseries now are investing in mycorrhiza and inoculating their stock to produce healthier plants that will transplant and take hold more easily when set in the ground.
The Destroying Angel (Amanita bisporigera syn. ocreata) mushroom looks rather harmless but as its’ name implies it is very deadly and should be one of the first an amateur mycologist should learn. Photo: Paul Maschka
Growing Culinary Mushrooms
Yes, it is possible to grow you own mushrooms. Many people, enticed by mushroom growing kits, have tried. Do know that they are very sensitive to the environment. Unless you plenty of time to monitor them, a shaded or dark area with constant moisture—not too much and not too little—and a sterile environment, you may be disappointed. They are very sensitive and not at all forgiving. One of the more popular mushrooms that has been grown successfully in San Diego and grows in native riparian areas is the oyster mushroom. The San Diego Mycological Society gives classes on growing your own mushrooms.
Mushrooms in the Wild
Even though we live in a dry climate, there are many types of mushrooms that are native to San Diego County. The San Diego Natural History Museum not only has an herbarium where they preserve examples of the native flora of the county, but also a mycorium where they are collecting and preserving dried examples of the mushrooms of the area. The collection now includes over 200 species, including the ever-popular slime mold (Fuligo septica—for those who care).
Fungi and mushrooms are actually an early indicator of the health of an environment. In a balanced natural ecosystem, mushrooms appear seasonally, mature, produce spore and then disappear until the next year. As we develop more and more of the native habitat, we destroy the environs in which these delicate fungi grow. While local governments are making some attempts to preserve our county’s unique vernal pools, there is yet to be a single notice of a threatened mushroom on the endangered species list. They are so ephemeral that even knowledgeable mycologists may miss their evident life cycle in a given year. Or, if conditions aren’t just right, they may decide to skip it for that year.
Hunting the Wild Mushroom
Mushroom hunting is an art and a science. Even experts who have been searching out these delectable morsels for many years always err on the side of caution. Paul Maschka, president of the San Diego Mycological Society shared their adage, “There are no old bold mushroom hunters.” If you like the idea of finding an exquisite tasting mushroom not found in the grocery store, join the society and train with the experts. While there are published keys to identifying mushrooms, some of the culinary ones are similar to those that are toxic, so take advantage of the experience of others.
Just a few deadly mushrooms grow in San Diego County. The most common one, Amanita ocreata, is the most deceptive because of its similarity to commercial mushrooms, particularly the portobello. It really looks like it should be edible instead of fatal. The few others which grow here aren’t nearly so common or as attractive.
There are also some choice culinary ones which are native. The lovely oyster mushrooms, Pleurotus ostreatus, is a symbiont of riparian willows. While it is distinctive, it also has pretenders. Delicious morels pop up occasionally, sometimes in areas that have been recently spread with a deep moist layer of bark mulch. The small, rather unimpressive looking candy cap (Lactarius rubidus) smells faintly of brown sugar or butterscotch. And, California has its own species of the popular porcini, Boletus dryophilus, symbiont of the coastal live oak.
In between there are mushrooms that won’t kill you, but there is no way on earth you would want to eat them. Nonetheless, they may sport brilliant colors, fascinating shapes, or a wide range of fragrances.
Typically, mushroom spores begin to develop in our rainy season. If you go looking, timing is paramount, as is location. They are most prolific in our native woodlands. Mushroom hunting connects us to our primeval ancestors. What better way to appreciate their knowledge, wisdom and skills in discovering and utilizing this natural food source. Even if you don’t find any, it’s a great way to get some exercise out in the woods, smell the fresh air and regain gratitude for our beautiful environment.
In Appreciation of Fungi
Beyond gustatory pleasures, mushrooms and fungi have contributed to our human experience in both basic and complex ways. Were it not for fungi we would have no wine, beer, bread, soy sauce, cheese or tofu.
Penicillin was one of the first pharmacological discoveries of western medicine. The pharmaceutical industry is only beginning to uncover some of the thousands of potent natural compounds produced by fungi and to realize their potential. Research continues on fungal compounds that may create immunity to some kinds of cancer, as example. From ancient times, Asian herbal medicine has included many fungus-based cures in powders, tinctures and other potions.
Myco-bioremediation is now being used for habitat restoration. Innoculation with the decomposing microorganisms and fungi has helped to greatly reduce organic debris in the wake of Hurricane Katrina. Specific organisms have been found to clean up oil spills more safely and quickly in water and soil. Because of the specificity of the compounds, some are being investigated for their potential as biodegradable insecticides. Who knows what we will discover in the future?
So next time you happen on a mushroom (toxic or not), give it a nod of thanks for helping us out in our lives and gardens.
Reprinted from January/February 2009, Volume 100, Number 1
SAN DIEGO FLORAL ASSOCIATION. This story may not be published in any form or copied onto another website without written permission from San Diego Floral Association.
Mission: To promote the knowledge and appreciation of horticulture and floriculture in the San Diego region.