Mushroom Hunter: Dr. H. D. Thiers

I learned about mushroom hunter, Dr. Harry D. Thiers (1919-2000), while researching bolete mushrooms for the dye project using Bolete edulis (See Dye Project: Bolete with Alum, Bolete with Titanium Oxalate, and Bolete with Ferrous Sulfate). Thiers was born January 22, 1919 in Fort McKavett, Texas. He received his B.A. degree from the University of Texas in 1941, served in the U.S. Navy from 1942-1945, and received an M.A. degree from the University of Texas in 1947. He earned his Ph.D. at the University of Michigan in 1956, studying under Dr. Alexander H. Smith. Dr. Thiers' doctoral dissertation was on the Agaricales (gilled mushrooms) of the pine belt in eastern Texas.

Dr. Thiers began his career as an academic at Texas A&M University, where he taught for 12 years. He moved to California in 1959, where he taught at San Francisco State University for 30 more years and served as major professor for 35 Master's Degree students. Upon his arrival at San Francisco State University, he began building an herbarium that now houses over 220,000 specimens (focusing on mushrooms collected across North America, Hawaii, and Indonesia). It was renamed the Harry D. Thiers Herbarium at San Francisco State University in 1989.

Dr. Harry D. Thiers

As a researcher, Dr. Thiers published books and papers in both leading scientific journals and lay publications. He specialized in the fleshy fungi of California. He was recognized worldwide as the leading authority on boletes and an innovator in the research on secotioid fungi. He identified over 150 new species of fungi based on material collected in Europe, Australasia and throughout North America. Fourteen different taxa are named in his honor, including the genus Thiersia. Dr. Thiers retired in 1989 but continued his work on California mycota. According to a tribute written by Michael Boom in 2000, Dr. Thiers died in his sleep at the age of 81. He was in Ohio with his wife Ellen, visiting his daughter and family. He had spent the previous day collecting and studying mushrooms with friends and family

Dr. Thiers (photo by Michael Wood)

I was interested to learn more about Dr. Thiers because of his specialization in Californian mushrooms, including boletes. Bolete edulis frequently pops up in our yard under the big oak tree; they are big and fleshy and grow very rapidly. I can see why they were of interest to him. I was also interested to learn about secotioid fungi. According to Wikipedia:

"Secotioid" refers to an intermediate fungal form between mushrooms (agarics) and truffle-like fungi (gasteromycetes), where the cap does not fully open. These fungi often retain a stipe (stem) but have enclosed, internal, or contorted gills that do not forcibly discharge spores, adapting them for arid environments.

What a fascinating adaptation for a very dry habitat! It made me realize that in all my trips to the dessert with my folks we never saw any mushrooms, although we may have seen secotioids without realizing what we were seeing. An example is Agaricus deserticola  (see: https://en.wikipedia.org/wiki/Agaricus_deserticola).

Learn More

• Bloom, Michael. "MSSF Mourns Harry Thiers". MykoWeb: Mushrooms, Fungi, Mycology website, 2000. Tribute to Dr. Thiers. See: https://www.mykoweb.com/articles/MSSF_Mourns.html

• Desjardin, Dr. Dennis. "Dr. Harry D. Theirs". MykoWeb: Mushrooms, Fungi, Mycology website, 1998. Description of Dr. Thiers' career and contributions. See: https://www.mykoweb.com/misc/HDTbyDED.html

• "Harry D. Thiers". Wikipedia website. Provides a brief biography of Thiers and references. See: https://en.wikipedia.org/wiki/Harry_D._Thiers

• "Overview, San Francisco State University, Harry D. Thiers Herbarium". NYBG Steere Herbarium. November 2017. See: https://sweetgum.nybg.org/science/ih/herbarium-details/?irn=125864

• "San Francisco State University, Harry D. Thiers Herbarium (SFSU)". Mycology Collections Portal. See: https://www.mycoportal.org/portal/collections/misc/collprofiles.php?collid=18

• Thiers, Dr. Harry D. "The Agaricales (Gilled Fungi) of California". Published as a multi-part series, or in multiple volumes. The most detailed taxonomic key for the region. See: https://www.scribd.com/document/28261601/Fungi-Books-Published-in-a-Series

• Thiers, Dr. Harry D. "California Mushrooms: A Field Guide to the Boletes". Macmillan Publishing Co., 1975. For an updated online version, see: https://www.mykoweb.com/boletes/

• Thiers, Harry D. and Smith, Alexander H. "The Boletes of Michigan". University of Michigan Press, 1970.

Field Notes for June 2026

 Welcome back to Field Notes!

June 1, 2026

Shopping at the Farmer's Market. This is a great time of year to shop the farmer's markets in Oakland and surrounding areas. The produce is beautiful, whether vegetables like broccoli, summer squash, and cucumbers, or fruit like blueberries, peaches, and melons. Time to put away the hearty recipes of fall and winter, and start using seasonal fruits and vegetables. Stir fry, spring rolls, grilled or steamed veg, and kabobs serve as healthy main dishes. Follow-up with fruit bowls, strawberry shortcake, homemade sorbet, or fruit pie for delectable desserts. Yum!

Spring-to-summer produce at the Montclair Farmer's Market

June 3, 2026

Cooking with Mushrooms. For my latest cooking-with-mushrooms adventure, I sourced 6 ounces (170g) of fresh shiitake mushrooms from the grocery store, and used them to make a delicious stir fry. Main ingredients included chopped chicken, mushrooms, pea pods, shredded cabbage, grated carrot, udon noodles and a teriyaki-inspired stir-fry sauce, garnished with dry-roasted peanuts. The shiitake mushrooms added a bold, fresh, umami flavor to the dish. The mushrooms were cultivated by the Far West Fungi company in Moss Landing, CA.

Shiitake grow in groups on the decaying wood of deciduous trees. Its natural distribution includes warm, moist climates in Southeast Asia. Prior to this experience, I had cooked only with reconstituted dried shiitake mushrooms, which are also delicious.

 

Shiitake Mushrooms (Lentinula edodes)

June 6, 2026

Big Bear Sighting in Juneau.  My brother Dave was hiking out by Mendenhall Glacier in Juneau, Alaska recently, and encountered this big guy on the trail. Dave's account of the experience:

I was out walking in the mossy forest by the glacier and was almost back to my car when I saw something coming towards me on the trail ahead. It’s a big ol’ bear, and he's seen me too and stopped. Then he starts walking towards me again. I’m pretty sure we’ve seen him before and he's always been a good bear, and there were no bad vibes here, so I stepped out of the trail and stood next to bushes where he could easily see me. I stood there taking pictures and started talking. I told him what a handsome fellow he was, and that I would just stand here by the side of the trail and let him walk on by like the good bear he is. He paused a moment to check me out, but I kept encouraging him to walk on by and that’s what he did. Maybe 400 pounds?
Life is good!

Big Bear at Mendenhall Glacier (photo by Dave Harris)

June 9, 2026

OTHG Hike to Reinhardt Redwood Park. I joined Mari and Gaymond for the Over-the-Hills Gang hike through the redwoods, led by Anthony Fisher. We followed the Stream Trail along the creek, which still has quite a bit of water. Our group was pretty good sized, and we sauntered through the cool forest at a very comfortable pace. I was eager to learn more about Mari's recent trip to England and Scotland, and Gaymond's earlier trip to Greece. We were joined by fellow hiker and traveler, Lorie, who had recently sailed across the Atlantic Ocean, skirting the Sargasso Sea, and then visited Spain and England.

Hike in the redwoods

A favorite highlight of this trail is seeing the ladybugs (Hippodamia convergens) that congregate at a particular location along the trail about this time of year. This time we didn't see any ladybugs, although someone with a sense of humor had left several plastic ladybugs at the location. Anthony brought ginger and lemon flavored cookies for the half-way point in our hike, and someone else brought Girl Scout peanut butter sandwich cookies (Do-si-dos). We feasted!

Can you spot the plastic ladybug?

Mari, Gaymond and I finished our outing with lunch and good conversation at nearby Sparky's Giant Burgers. These hikes are so much fun, and the pace and company are excellent. Check the website to learn more about upcoming events at East Bay Parks.

June 12, 2026

Happy Birthday to my wonderful sister, Marianne! She is so much fun to be with, capable and accomplished, spirited and adventurous. We don't see each other very often, but it is such a pleasure when we do. Marianne works hard, loves her kids and grandkids, and deserves all good things. I'm looking forward to our next visit!

Picnic with my sister at Point Pinole a few years back!

June 15, 2026

Invasion of the Giant Puffballs. Bobo the Husky and I encountered several of these Giant Puffball on our morning walk (possibly Calvatia gigantea or Calvatia booniana). They were growing in the small redwood and oak grove by the upper reservoir. This one was about five inches across, but they can get much bigger (up to 19 1/2 inches, according to iNaturalist).

Giant Puffball

June 17, 2026

We Love Washing Windows. Bobo the Husky was temporarily displaced by a visit from a team of window washers. He was so interested in the whole process, and all the tools involved. Bobo volunteered to help but got to relax and watch instead!

We Love Washing Windows

June 21, 2026 🌷

Happy summer solstice - enjoy the longest day of the year and the official start of summer!

Dye Project: Bolete with Ferrous Sulfate

For my third mushroom dyeing project, I again decided to use the Boletus edulis that had popped up under the oak tree in our yard after fall and winter rains, and to recycle another cotton dish towel from my stash. The dish towel had been mordanted with alum, and I planned to use ferrous sulfate (iron) as a mordant additive for this dye experiment.

A Boletus edulis under the oak tree

Greenish-yellow mushroom underside

The dye color for B. edulis comes from the mushroom cap underside, which is very spongy. I separated the spongy underside to harvest the dye material. The color is greenish-yellow.

Extract the Dye

For this project, I had previously extracted the mushroom dye, and divided it for three different projects (with the plan to use alum, titanium oxalate, and ferrous sulfate as three separate mordant additives). For information about extracting the dye, see Dye Project: Bolete with Alum, the "Extract the Dye" section. Note that a film of mold had started to grow on the surface of the dye liquid, but I just skimmed it off. The pH of the liquid still registered 3 (moderately acid).

Dye the Fabric

Dye the fabric with the mushroom dye liquid. For this experiment, I recycled a cotton dish towel that had been mordanted with alum and then dyed with the second extract of logwood with an iron mordant additive, which had produced a pale gray [see Dye Project: Logwood Exhaust 2 (Alum + Iron)]. I used the remaining third of the dye and added ferrous sulfate as a mordant additive.

Ferrous sulfate (or iron) is known for "saddening" or darkening the dye. It produces a deeper tonal range or gives a gray/brown cast to a color. More on ferrous sulfate.

Boletus dye pot with ferrous sulfate additive

Place the extracted mushroom dye in a dye pot and stir in a pinch (about 1/4 teaspoon) of ferrous sulfate as an additive. I tested the pH of the liquid, which still registered 3. Meanwhile, place the dish towel in clear water to soak for 20-30 minutes, to enable the fibers to soak up the dye.

Heat the mushroom dye to 185 °F (this takes about an hour to reach the temperature). Squeeze out the wet towel, and place it in the dye. Simmer for one hour, maintaining the temperature at 185°. Add water periodically to keep the fabric covered with dye extract.

Steep the cotton fabric overnight

Turn off the heat and steep the fabric overnight. The next day, squeeze out excess dye, rinse the fabric, and then run it through the washing machine (cold water only), and hang to dry.

Full disclosure: I wasn't thinking, and actually added a mild textile soap [like Synthropol or Professional Textile Detergent (a.k.a., Dharma Dyer's Detergent)] to the rinse, and then dried the towel in the dryer (I usually just rinse and hang to dry, and then wash in mild detergent two weeks later, giving the dye time to set). It seemed to work OK, but was not my usual process.

Squeeze out excess dye and rinse thoroughly

The resulting color was a pale gray when wet (although slightly darker than the original), but it dried to a lighter shade. The photo really doesn't capture the actual color. Once again I wondered if the mushroom dye actually dyed the fabric at all, or did it simply cause a slight over-dye reaction with the previous Logwood extract dye?

The resulting color is pale gray (although slightly darker)

In summary, these three experiments using Boletus mushrooms have been interesting. I can't really tell if any actual dyeing happened, or were the original colors simply changed or intensified by the mordant additives (alum, titanium oxalate, and ferrous sulfate). So far I have to concur with the literature that mushroom dyes do not work as well with cotton fiber as protein fiber. For future mushroom dyeing projects, I plan to use protein fibers (silk and wool), which are known to respond well to mushroom dyes and are typically color and light fast. For the previous Boletus projects see: Dye Project: Bolete with Alum and Dye Project: Bolete with Titanium Oxalate.

Summer Watch

Another trip around the sun and we're back and ready for summer! There is something very pleasing about the cyclical march of seasons through the year. Each season is unique across the four seasons, and decidedly unique from year to year.

Summer represents freedom to me, with its long days and warm, mild weather. Favorite past times include spending time outdoors, hiking (especially near the water), travelling, hanging out on the patio with my family, and exploring new things. It's also a great time to mix up the dinner menu, swapping out hearty meals for lighter fare with lots of fruits and vegetables and barbecue.

Birds are busy nesting this time of year, and stop for a quick bite

Join me in the garden to watch plants and critters go through their life cycles, and to count down to the summer solstice!