Mushrooms and Mosses

This is sort of two posts in one—reviews of a couple of books I got when I was in the Pacific Northwest last fall. They are Mycophilia: Revelations from the Weird World of Mushrooms by Eugenia Bone, and Gathering Moss: A Natural and Cultural History of Mosses by Robin Wall Kimmerer.

I like learning about living things, and mushrooms and mosses seemed like a good fit for the damp forests of the Pacific Northwest. I got quite a few books on that trip. Other reviews of books I got there are in the following posts:

• A Winter in Arabia by Freya Stark
• Waves and Beaches
• Also I got a book on Go and a novel from Orkney that I haven't reviewed

Mushrooms

I was motivated to read Mycophilia in part because I think fungi are going to be the next big thing* (as a meat alternative, biotechnology, remediation aid, and source of renewable materials). I own some shares in a mushroom farm. A neighbour of mine has a mushroom biotechnology company. Yeast are a fungi, and have been instrumental in biotech from the beginning to the cutting edge.

* I think another "next big thing" will be insect protein (for animal feed or even human food), but that's a story for another day.

Eugenia Bone has a long personal history with fungi, driven by her love of eating mushrooms. She went from casual foraging to attending foray events and mushroom conferences and eventually became the president of the New York Mycological Society. That personal journey informs and structures Mycophilia. As research for one chapter she even tripped on mushrooms.

The book covers a wide range of fungi, and some chapters delve into the industries around wild foraging, mushroom cultivation, "mycotechnologies" (fungal biotech), their nutritional value, and diseases—and medicines—from fungi. The author also spends a lot of time describing various mushroom festivals and conferences and the personalities that attend them. Overall, I found it to be a unique but interesting read. I learned a lot, too; I'll attempt to summarize the most interesting parts in the following points:

• As a point of terminology, fungus and mushroom are not synonyms: mushrooms are the fruiting body, while the whole organism is the fungus; not all fungi have mushrooms.
• A typical fungal life-cycle involves mycelium, a web of single-cell-wide hyphae, spreading out as it consumes its food source. If hyphae from two different fungi of the same species fuse together, they can share genetic material and go on to form a node that expands into a mushroom. The mushroom disperses spores (and the techniques for doing this are incredibly diverse) that can start a new mycelium if they land in ideal conditions (which is very rare, so the number of spores produced is astronomical).
• Fungi live in their food source (substrate).
• Fungi can be categorized as Mycorrhizal, Saprophytic, and Endophytic. The latter live between the cells of plants without causing disease, and are poorly understood.
• Mycorrhizal fungi live in association with the roots of plants, and play an important role in transferring nutrients from the soil to the plant (or even between trees). In return, they get sugars from the plant. This symbiotic relationship is vital in the poor soils of the Amazon rainforest, for example. Trees can be inoculated with their symbiotic fungi by dipping the roots in a broth of spores before planting (either to benefit the tree or to grow the fungus, e.g. truffles).
• Saprophytic fungi are the decomposers, and include most familiar species (button mushrooms, yeast, mold). They can collectively (each one is quite specialized) break down most organic compounds imaginable with their battery of enzymes.
• Mushroom foraging is a big business. Morels are a notable variety that is wild-harvested. They grow in great numbers in the western US following forest fires, and roving camps of pickers (including a lot of south-east Asians) move around to where the harvest is best.
• Mycorrhizal species (and semi-mycorrhizal ones such as morels) haven't been reliably cultivated. The requirement to forage for them means that in-demand kinds like truffles can be very expensive. Most cultivated kinds of mushrooms are saprophytes.
• Mushroom cultivation is a matter of mixing pasteurized substrate with spawn (germinated spores) in a suitable environment. Kennett Square PA is a centre of mushroom cultivation as the home of Phillips Mushroom Farms and the nearby Lambert Spawn.
• White button mushrooms almost all come from a single spore, selected for colour, high yield, and disease resistance. The same species also gives us crimini mushrooms (brown in colour) and portobellos (when mature).
• Part of the appeal of truffles (to pigs and people) is that they give off imitation pheromones.
• An important aspect of the nutritional value of mushrooms is that they are a source of all nine essential amino acids, making them a valuable meat substitute.
• Fungal diseases are difficult to treat because they have similar biochemistry to animals so effective antibiotics would also target the cells of the patient.
• The book had an interesting aside on our gut fauna ("microbiome"), although it is mainly bacterial rather than fungal.
• There are many emerging biotech applications for fungi, including remediation of contaminated sites. A particularly creative application is growing insulation/packing materials.

This is a neat concept:

"The law of microbial infallibillity," said Tom Volk, "says if a substrate exists in nature, there is a microbe that can degrade it."

One thing it would have been nice to see in the book is a chapter on yeast.

The final chapter of the book carries this unforgettable description of a certain mushroom: "basically sex plus water".

From reading Mycophilia, I came up with a list of a dozen mushrooms to know (disclaimer: get a proper guide if you plan on foraging):

1. Agaricus bisporus = button mushrooms, crimini, portobello; cultivated
2. Pleurotus ostreatus = oyster mushrooms, a type of white-rot fungi; cultivated
3. Lentinula edodes = Shiitake; cultivated
4. Penicillium = a genus of mold used in making antibiotics and blue cheese
5. Saccharomyces = yeasts used in baking and brewing
6. Flammulina velutipes = Enoki; cultivated
7. Morchella = morels; foraged
8. Tuber = truffles; foraged
9. Cantharellus cibarius = chanterelle; foraged
10. Boletus edulis = porcini; foraged
11. Amanita = a genus that includes deadly poisonous and hallucinogenic species
12. Psilocybe = genus of magic mushrooms

Although Mycophilia is not a recipe book, it did include some appetizing descriptions of mushroom dishes, including:

• grilled porcini caps and eggplant, ground up with garlic, salt, and lemon juice and used as a dip.
• morels stuffed with cream cheese, crab, and shrimp, and southwest seasoning then slow-smoked (make sure the morels are thoroughly cooked)
• yellowfoot mushrooms and filet of sole cooked in parchment with white wine and thyme
• pig stuffed with porcini stems, garlic, thyme, and sage, baked in a fire pit
• matsutake steamed in soy and rice wine

Note that Mycophilia carries an important disclaimer on its copyright page:

This is not a guidebook and should not be used to identify mushrooms. Nor should the reader think that because the author ate a wide variety of wild mushrooms they would have the same results. Meaning, while I lived to tell the tale, you might not.

Mosses

The author of Gathering Moss is a moss researcher. She's also a woman with aboriginal heritage and brings both these perspectives into the book. Each chapter is written as an essay, describing a certain type of moss or moss characteristics along with stories of fieldwork or reflections on life. The scientific themes in the book include ecological niches, microclimates, and disturbance and recovery.

Here are some of the things I found interesting in this book:

• Like snowflakes, mosses look better under magnification.
• There is sort of a fractal aspect to mosses in the way their structure is similar to that of the forest at large.
• This book mentions research that the author did on Adirondack mosses, so I found the paper. I also found some of her other publications.
• Because mosses are close to the ground, they exist in the boundary layer (with respect to air currents), which is sort of a microclimate with less wind and evaporation, more warmth, and more CO2—all of which make for a more favourable place for small plants to grow.
• Mosses are shade tolerant, so they grow well under evergreens.
• They play a useful role in ecological succession (such as reforestation after a disturbance) by trapping seeds in a moist environment.
• Mosses are sort of the amphibians of the plant kingdom in that their lifecycle requires them to return to the water (or at least be well soaked) for reproduction; they have male and female shoots that can only achieve fertilization when they are bridged by water drops.
• Sexual reproduction results in spores that can be scattered afield, but many mosses are also capable of asexual reproduction by shedding buds or fragments that can then regrow.
• Moss also need to be wet to carry out photosynthesis and gas transfer (absorbing CO2). (i.e. gas transfer is necessary for photosynthesis and can only happen when wet).
• Although their activity ceases when they dry out, mosses can survive dessication and resume activity when they get wet again. This is also true for "water bears" (tardigrades), which often inhabit mosses.
• The author's PhD research was very interesting; it was on vertical stratification of moss species in a flood zone, related to the "intermediate disturbance hypothesis" (the hardiest species dominated the frequently flooded zone, the most competitive species dominated the zone that was mostly safe from flood damage, but in the intermediate zone there was a wide mix of species).
• Another interesting bit of research described in Gathering Moss was on Tetraphis spp., which switches its reproductive modes (from asexual clones to sexual spores) based on its density—filling in the nearby environment when less dense and sending spores further away when dense. Dr. Kimmerer describes how she came to this conclusion by "looking at it from the moss' perspective", since there were no changes in external factors (light levels, pH, temperature, etc.) to explain the shift.
• It is interesting that ecological processes such as gap dynamics scale down to the level of mosses. The book contains a nice description of the dynamics of beech-birch-maple forests.
• The similarity of urban and cliff ecosystems was noted, including in the mosses found there.
• Mosses can indicate air pollution. They are highly sensitive, since they are 1 cell thick and have to be moist for good gas transfer—like lungs. Cities with no moss may be hard on people with respiratory problems.
• Indigenous uses of moss were as diapers and sanitary napkins; as these fell under women's domain they were often overlooked by many male explorers and anthropologists compared to other plant uses.
• The author shares her indigenous perspective of plants having a purpose, in the environment and for humanity (rather than seeing humanity isolated from the rest of creation). The teleology of moss in this perspective has to do with its ability to absorb large quantities of water.
• In an interesting chapter on bogs, I learned that sphagnum actually creates its own preferred environment, binding up water in its dead cells to keep things wet, lowering pH and promoting anaerobic conditions (shutting out competition and slowing decay—since it needs a long thread of dead-but-not-decayed cells to make the "sponge" of the bog)
• There are challenges in growing moss purposefully, since only a lucky few of the myriads of spores successfully "take". One suggested technique is making a moss milkshake to propagate moss (since they can regrow from fragments).
• I was interested to learn of the role of moss in the phosphorus cycle: it captures runoff and nutrients can be transferred (by fungi) to the roots of trees. Water purification possibilities are also mentioned.

Next to the scientific explanations in Gathering Moss, there are philosophical and sensory passages like the following:

There is an ancient conversation going on between mosses and rocks, poetry to be sure. About light and shadow and the drift of continents. This is what has been called the "dialectic of moss on stone—an interface of immensity and minuteness, of past and present, softness and hardness, stillness and vibrancy, yin and yang."

Reading this book motivated me to get a magnifying glass and go out in the woods to look at mosses in the summer. And try to see unique features rather than a generic green carpet.

Spores

Reading these two books around the same time made for a neat comparison. Fungi and mosses actually have quite a bit in common. They have complex lifecycles involving spores along with significant reliance on asexual reproduction. For both of them, there is a growing recognition of the valuable ecosystem services they provide, as well as some interest in deliberately applying them for remediation and other purposes. However, they are currently at the limits of agriculture, so to speak, as they are difficult to reliably cultivate. From both these books I learned more about how life fills so many diverse niches in fascinating ways.

To compare the books, I'd say Mycophilia was a quick read, while Gathering Moss was more deliberative/meditative (but conveniently divided into short essays). I thought both did a good job explaining the scientific concepts clearly.

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